(In reply to comment #421)
> I have suffered the high iowait problem for almost 4 years
Then let's finally kill it!

> I got information from this bugzilla report that kernel 2.6.32 has fixed
> this high iowait problem, and I tested the snapshot kernel 2.6.32.2 of
> zenwalk
> on my notebook, and found the high iowait is gone

> I found in kernel 2.6.32.8 the high iowait is back. How do I know
> that? When I copy a 700MB avi file from my notebook disk to a 3.5" usb
> mobile disk, I found the reading side disk LED start to falsh quickly and
> immediately, but the writing side disk LED will keep still for a long
> time(like
> 25-30 seconds), and then start to flash slowly,and the course is abnormally
> long and low responsive.

> The kernel 2.6.32.2 is the only 2.6 kernel (since 2.6.18) on which I found
> both of the reading and writing side disk LED will start to falsh
> quickly and immediately.There must be somthing wrong with the write
> cache behavior which will cause the high iowait, and it has been fixed in
> 2.6.32.2 and brought back in 2.6.32.8.

This is the complete git log 2.6.32.2..2.6.32.8:
b0e4370 Linux 2.6.32.8
6117db7 NET: fix oops at bootime in sysctl code
e4a6a35 powerpc: TIF_ABI_PENDING bit removal
a420e9f ath9k: fix beacon slot/buffer leak
1c97637 ath9k: fix eeprom INI values override for 2GHz-only cards
2c7f87e pktcdvd: removing device does not remove its sysfs dir
b31aa5c uartlite: fix crash when using as console
e06fbe9 kernel/cred.c: use kmem_cache_free
35cfb03 starfire: clean up properly if firmware loading fails
906f68d mx3fb: some debug and initialisation fixes
682efb8 imxfb: correct location of callbacks in suspend and resume
b260729 mac80211: fix NULL pointer dereference when ftrace is enabled
3a9353f mm: flush dcache before writing into page to avoid alias
78da404 be2net: Fix memset() arg ordering.
e38d76e be2net: Bug fix to support newer generation of BE ASIC
43d7ff2 connector: Delete buggy notification code.
f06f00e usb: r8a66597-hdc disable interrupts fix
0ae2b7d block: fix bugs in bio-integrity mempool usage
9648148 random: Remove unused inode variable
8857a1a random: drop weird m_time/a_time manipulation
94af44b Fix 'flush_old_exec()/setup_new_exec()' split
cb723ba block: fix bio_add_page for non trivial merge_bvec_fn case
e52299d mm: purge fragmented percpu vmap blocks
56d4b77 mm: percpu-vmap fix RCU list walking
dce6a09 libata: retry link resume if necessary
42f7e23 oprofile/x86: fix crash when profiling more than 28 events
9c66557 oprofile/x86: add Xeon 7500 series support
4f7d666 KVM: allow userspace to adjust kvmclock offset
a74e62c ax25: netrom: rose: Fix timer oopses
3125258 af_packet: Don't use skb after dev_queue_xmit()
ecb7287 net: restore ip source validation
1681333 sky2: Fix oops in sky2_xmit_frame() after TX timeout
16b8efa tcp: update the netstamp_needed counter when cloning sockets
359e2f2 clocksource: fix compilation if no GENERIC_TIME
253f887 x86/amd-iommu: Fix possible integer overflow
d1a3103 x86: Add quirk for Intel DG45FC board to avoid low memory corruption
8159070 x86: Add Dell OptiPlex 760 reboot quirk
00362b9 regulator: Specify REGULATOR_CHANGE_STATUS for WM835x LED constraints
6db6ace SECURITY: selinux, fix update_rlimit_cpu parameter
80569f6 firewire: core: add_descriptor size check
612e99b drm/i915: only enable hotplug for detected outputs
69bf9a6 iwlwifi: set default aggregation frame count limit to 31
3492bbb x86: Disable HPET MSI on ATI SB700/SB800
cf135e5 Input: winbond-cir - remove dmesg spam
5e806e1 x86: get rid of the insane TIF_ABI_PENDING bit
c2e245d sparc: TIF_ABI_PENDING bit removal
336ca4c Split 'flush_old_exec' into two functions
944a638 FDPIC: Respect PT_GNU_STACK exec protection markings when creating NOMMU stack
0b3bf81 mm: fix migratetype bug which slowed swapping
629527c Fix failure exit in ipathfs
30d3844 fix affs parse_options()
d842c31 Fix remount races with symlink handling in affs
36a0a4a fix leak in romfs_fill_super()
26d2257 fix oops in fs/9p late mount failure
deb20f1 Fix failure exits in bfs_fill_super()
703c300 Fix a leak in affs_fill_super()
61d4374 drm/i915: Reload hangcheck timer too for Ironlake
f0b4195 e1000/e1000e: don't use small hardware rx buffers
b9ad9bb e1000e: enhance frame fragment detection
dff2267 e1000: enhance frame fragment detection
cfc7e54 UBI: fix volume creation input checking
3b4f785 ACPI: Advertise to BIOS in _OSC: _OST on _PPC changes
0d48a1a ACPI: fix OSC regression that caused aer and pciehp not to load
1a52add ACPI: Add platform-wide _OSC support.
e62a96c ACPI: Add a generic API for _OSC -v2
1e88960 dasd: fix possible NULL pointer errors
083beff zcrypt: Do not remove coprocessor for error 8/72
63693ee libata: retry FS IOs even if it has failed with AC_ERR_INVALID
8c2cd3f x86: Remove "x86 CPU features in debugfs" (CONFIG_X86_CPU_DEBUG)
b5b39c3 x86: Set hotpluggable nodes in nodes_possible_map
76e789c S390: fix single stepped svcs with TRACE_IRQFLAGS=y
16a2ae6 firewire: ohci: fix crashes with TSB43AB23 on 64bit systems
d8e0902 drm/i915: Selectively enable self-reclaim
8268c0b mm: add new 'read_cache_page_gfp()' helper function
b7a9d92 mptsas: Fix issue with chain pools allocation on katmai
e15fca0 scsi_lib: Fix bug in completion of bidi commands
b4bdd73 Linux 2.6.32.7
a8e96d6 x86, msr/cpuid: Pass the number of minors when unregistering MSR and CPUID drivers.
0a1c275 fnctl: f_modown should call write_lock_irqsave/restore
01e991b iwlwifi: Fix throughput stall issue in HT mode for 5000
d274df6 ACPI: enable C2 and Turbo-mode on Nehalem notebooks on A/C
59568be x86: Reenable TSC sync check at boot, even with NONSTOP_TSC
194223f IPoIB: Clear ipoib_neigh.dgid in ipoib_neigh_alloc()
454f8b1 KVM: only clear irq_source_id if irqchip is present
eaccd49 KVM: fix lock imbalance in kvm_*_irq_source_id()
9801911 KVM: x86: Fix leak of free lapic date in kvm_arch_vcpu_init()
8e5c20d KVM: x86: Fix probable memory leak of vcpu->arch.mce_banks
0118bac KVM: x86: Fix host_mapping_level()
4938210 KVM: MMU: bail out pagewalk on kvm_read_guest error
59cf854 KVM: Fix race between APIC TMR and IRR
f0d13b8 KVM: only allow one gsi per fd
70be4d7 KVM: S390: fix potential array overrun in intercept handling
eb60025 cfg80211: fix channel setting for wext
304cd19 mac80211: check that ieee80211_set_power_mgmt only handles STA interfaces.
09e4d0f ASoC: fix a memory-leak in wm8903
2cdc2dc UBI: initialise update marker
f6fbe0b UBI: fix memory leak in update path
4d845d6 hwmon: (fschmd) Fix a memleak on multiple opens of /dev/watchdog
00bd133 ALSA: hda - Fix HP T5735 automute
a0dffef ipc ns: fix memory leak (idr)
a5981df netiucv: displayed TX bytes value much too high
27aeefb cio: dont panic in non-fatal conditions
f5b1bc5 cio: fix double free in case of probe failure
da02974 V4L/DVB (13826): uvcvideo: Fix controls blacklisting
2928b68 md: fix small irregularity with start_ro module parameter
31cf6d8 ata_piix: fix MWDMA handling on PIIX3
3de08a12 ahci: disable SNotification capability for ich8
c817c19 iTCO_wdt: Add Intel Cougar Point and PCH DeviceIDs
42b4505 iTCO_wdt: add PCI ID for the Intel EP80579 (Tolapai) SoC
53691f2 iTCO_wdt.c - cleanup chipset documentation
4220098 ALSA: hda - Add missing Line-Out and PCM switches as slave
9049580 ALSA: hda - Fix quirk for Maxdata obook4-1
a2c5952 ALSA: hda - select IbexPeak handler for Calpella
d160610 Input: i8042 - add Dritek quirk for Acer Aspire 5610.
461eb3f Input: i8042 - add Gigabyte M1022M to the noloop list
f6278f1 Input: i8042 - remove identification strings from DMI tables
44d13be DMI: allow omitting ident strings in DMI tables
5172b4b PCI: AER: fix aer inject result in kernel oops
bf9a88d qlge: Bonding fix for mode 6.
6b07617 qlge: Add handler for DCBX firmware event.
6055e7f qlge: Don't fail open when port is not initialized.
836750b qlge: Set PCIE max read request size.
ffd1fab qlge: Remove explicit setting of PCI Dev CTL reg.
7c0798e fcoe: Fix getting san mac for VLAN interface
1ce0348 fcoe: Fix checking san mac address
e166cb1 fcoe, libfc: fix an libfc issue with queue ramp down in libfc
2792e0ce libfc: remote port gets stuck in restart state without really restarting
407590a libfc: fix free of fc_rport_priv with timer pending
a3d46ca libfc: fix memory corruption caused by double frees and bad error handling
4c40dbe libfc: Fix frags in frame exceeding SKB_MAX_FRAGS in fc_fcp_send_data
88cc93a fcoe: initialize return value in fcoe_destroy
7c8a0dc libfc: don't WARN_ON in lport_timeout for RESET state
83d236b libfc: lport: fix minor documentation errors
56320f6 libfc: Fix wrong scsi return status under FC_DATA_UNDRUN
d5d72da fcoe: remove redundant checking of netdev->netdev_ops
34556a1 libfc: fix ddp in fc_fcp for 0 xid
1e418b2 libfc: fix typo in retry check on received PRLI
253f41b lpfc: fix hang on SGI ia64 platform
4b2bc96 scsi_transport_fc: remove invalid BUG_ON
d502a76 scsi_dh: create sysfs file, dh_state for all SCSI disk devices
e7c8167 scsi_devinfo: update Hitachi entries (v2)
001252f HID: fixup quirk for NCR devices
5e05787 NFS: Revert default r/wsize behavior
1d42a1b iscsi class: modify handling of replacement timeout
83886fa PCI: Always set prefetchable base/limit upper32 registers
5cf92e9 timers, init: Limit the number of per cpu calibration bootup messages
34911bf nfsd: Fix sort_pacl in fs/nfsd/nf4acl.c to actually sort groups
a9238ce nohz: Prevent clocksource wrapping during idle
db47a16 sched: Fix missing sched tunable recalculation on cpu add/remove
08b84be sched: Fix isolcpus boot option
eb9dbd9 ALSA: ice1724 - Patch for suspend/resume for ESI Juli@
e96610c partitions: use sector size for EFI GPT
6f8de29 partitions: read whole sector with EFI GPT header
8f2fefc netfilter: xtables: fix conntrack match v1 ipt-save output
3cd4bea V4L/DVB (13680b): DocBook/media: create links for included sources
35f42c9 V4L/DVB (13680a): DocBook/media: copy images after building HTML
857ffb8 atl1e:disable NETIF_F_TSO6 for hardware limit
f7b1714 atl1c:use common_task instead of reset_task and link_chg_task
b68f619 iTCO_wdt: Add support for Intel Ibex Peak
96ef353 V4L/DVB (13168): Add support for Asus Europa Hybrid DVB-T card (SAA7134 SubVendor ID: 0x1043 Device ID: 0x4847)
8429570 USB: ftdi_sio: add USB device ID's for B&B Electronics line
5bcaffb USB: mos7840: add device IDs for B&B electronics devices
4d3c678 V4L/DVB (13569): smsusb: add autodetection support for five additional Hauppauge USB IDs
ff23399 ALSA: hda - Add PCI IDs for Nvidia G2xx-series
4bc685e vfs: get_sb_single() - do not pass options twice
1b715f1 driver-core: fix devtmpfs crash on s390
da30443 Driver-Core: devtmpfs - set root directory mode to 0755
04daa51 Input: ALPS - add interleaved protocol support (Dell E6x00 series)
30dc12e davinci: dm646x: Add support for 3.x silicon revision
c375e84 powerpc/fsl: Add PCI device ids for new QoirQ chips
a98917c ar9170: Add support for D-Link DWA 160 A2
002464c mpt2sas: New device SAS2208 support is added
90ee3ca be2net: Add the new PCI IDs to PCI_DEVICE_TABLE.
879c8e8 be2net: Add support for next generation of BladeEngine device.
c97c73d sfc: Fix DMA mapping cleanup in case of an error in TSO
9396c90 ACPI: don't cond_resched if irq is disabled
ce946bc clockevents: Add missing include to pacify sparse
08b8ff4 clockevent: Don't remove broadcast device when cpu is dead
f584d37 Linux 2.6.32.6
9607f06 perf: Honour event state for aux stream data
b0a9392 perf events: Dont report side-band events on each cpu for per-task-per-cpu events
5a20267 perf timechart: Use tid not pid for COMM change
f2fa92b vmalloc: remove BUG_ON due to racy counting of VM_LAZY_FREE
3d0cc9a USB: fix usbstorage for 2770:915d delivers no FAT
538a6fd x86/PCI/PAT: return EINVAL for pci mmap WC request for !pat_enabled
e0f5cfa DM: Fix device mapper topology stacking
fbe2992 block: bdev_stack_limits wrapper
ed0cd89 drm/i915: try another possible DDC bus for the SDVO device with multiple outputs
4fb77a3 drm/i915: Read the response after issuing DDC bus switch command
8cef765 SCSI: enclosure: fix oops while iterating enclosure_status array
5f0ab2d ACPI: EC: Add wait for irq storm
1ff7b99 ACPI: EC: Accelerate query execution
111ab4b USB: add speed values for USB 3.0 and wireless controllers
a2a5b33 USB: add missing delay during remote wakeup
bfec5ce USB: EHCI & UHCI: fix race between root-hub suspend and port resume
07d577f USB: EHCI: fix handling of unusual interrupt intervals
186c74d USB: Don't use GFP_KERNEL while we cannot reset a storage device
fa68188 USB: fix bitmask merge error
911b8be usb: serial: fix memory leak in generic driver
04f7ec7 serial: 8250_pnp: use wildcard for serial Wacom tablets
6fc7937 nozomi: quick fix for the close/close bug
8c53542 ecryptfs: initialize private persistent file before dereferencing pointer
3621216 ecryptfs: use after free
179b7e5 tty: fix race in tty_fasync
b70922a Staging: hv: fix smp problems in the hyperv core code
50e4975 Staging: asus_oled: fix oops in 2.6.32.2
ccb90b8 V4L/DVB (13900): gspca - sunplus: Fix bridge exchanges.
d547e91 x86, msr/cpuid: Register enough minors for the MSR and CPUID drivers
a2febcd Linux 2.6.32.5
af55a3d vfs: Fix vmtruncate() regression
2693139 sched: Fix task priority bug
fdc360e serial/8250_pnp: add a new Fujitsu Wacom Tablet PC device
2d22b38 i2c/pca: Don't use *_interruptible
c1f77a7 i2c: Do not use device name after device_unregister
4bff5ff sparc64: Fix Niagara2 perf event handling.
9d6567c sparc64: Fix NMI programming when perf events are active.
896fb0d sched: Fix cpu_clock() in NMIs, on !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
9fc68ca asus-laptop: add Lenovo SL hotkey support
2196ca4 Input: pmouse - move Sentelic probe down the list
94249e6 megaraid_sas: remove sysfs poll_mode_io world writeable permissions
2db740c PCI/cardbus: Add a fixup hook and fix powerpc
eecd8a9 HID: add device IDs for new model of Apple Wireless Keyboard
781d5c4 reiserfs: truncate blocks not used by a write
56a7f72 V4L/DVB (13868): gspca - sn9c20x: Fix test of unsigned.
fe52cee ALSA: hda - Fix missing capture mixer for ALC861/660 codecs
34e7aa0 mfd: Correct WM835x ISINK ramp time defines
33faa3c mfd: WM835x GPIO direction register is not locked
7f08f93 x86: SGI UV: Fix mapping of MMIO registers
7f40c6b edac: i5000_edac critical fix panic out of bounds
25d5699 x86, apic: use physical mode for IBM summit platforms
c91ab04 page allocator: update NR_FREE_PAGES only when necessary
d4c893f futexes: Remove rw parameter from get_futex_key()
8410b13 x86, mce: Thermal monitoring depends on APIC being enabled
1bd24fd block: Fix incorrect reporting of partition alignment
8a9c3f5 drm/i915: remove loop in Ironlake interrupt handler
4334ab7 memcg: ensure list is empty at rmdir
70f800f revert "drivers/video/s3c-fb.c: fix clock setting for Samsung SoC Framebuffer"
800c028 inotify: only warn once for inotify problems
cec3ad6 inotify: do not reuse watch descriptors
3df7673 Linux 2.6.32.4
5877960 agp/intel-agp: Clear entire GTT on startup
5deb72e ipv6: skb_dst() can be NULL in ipv6_hop_jumbo().
54f1b39 module: handle ppc64 relocating kcrctabs when CONFIG_RELOCATABLE=y
9ef9a7c fix more leaks in audit_tree.c tag_chunk()
dffaea5 fix braindamage in audit_tree.c untag_chunk()
d3b1e3b mac80211: fix skb buffering issue (and fixes to that)
71c7707 kernel/sysctl.c: fix stable merge error in NOMMU mmap_min_addr
904e373 libertas: Remove carrier signaling from the scan code
b9945e7 drm/i915: remove render reclock support
9b13cca mac80211: add missing sanity checks for action frames
0ea5505 iwl: off by one bug
724ad42 cfg80211: fix syntax error on user regulatory hints
e6efac7 ath5k: Fix eeprom checksum check for custom sized eeproms
fc95845 iwlwifi: fix iwl_queue_used bug when read_ptr == write_ptr
a111c28 xen: fix hang on suspend.
38c4d8d quota: Fix dquot_transfer for filesystems different from ext4
a61dcb0 hwmon: (adt7462) Fix pin 28 monitoring
4052fbf hwmon: (coretemp) Fix TjMax for Atom N450/D410/D510 CPUs
545b020 netfilter: nf_ct_ftp: fix out of bounds read in update_nl_seq()
635b4f9 netfilter: ebtables: enforce CAP_NET_ADMIN
954c8ef ASoC: Fix WM8350 DSP mode B configuration
cf99848 ALSA: atiixp: Specify codec for Foxconn RC4107MA-RS2
0385cc0 ALSA: ac97: Add Dell Dimension 2400 to Headphone/Line Jack Sense blacklist
5bb4e84 ALSA: hda - Fix ALC861-VD capture source mixer
e0abcea mmc_block: fix queue cleanup
0c74f45 mmc_block: fix probe error cleanup bug
0798abf mmc_block: add dev_t initialization check
0696a3b kernel/signal.c: fix kernel information leak with print-fatal-signals=1
ecac13f dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE and
f21efc5 lib/rational.c needs module.h
21f7654 cgroups: fix 2.6.32 regression causing BUG_ON() in cgroup_diput()
6abb6ac drivers/cpuidle/governors/menu.c: fix undefined reference to `__udivdi3'
fdc0895 rtc_cmos: convert shutdown to new pnp_driver->shutdown
0c51b5c drm/i915: fix unused var
c7e8c26 drm/i915: Select the correct BPC for LVDS on Ironlake
c04fd30 drm/i915: Make the BPC in FDI rx/transcoder be consistent with that in pipeconf on Ironlake
cba0270 drm/i915: Enable/disable the dithering for LVDS based on VBT setting
de04091 drm: remove address mask param for drm_pci_alloc()
c693959 drm/i915: Permit pinning whilst the device is 'suspended'
d241962 drm/i915: fix order of fence release wrt flushing
d3e4d5f drm/i915: Update LVDS connector status when receiving ACPI LID event
8064af1 sunrpc: on successful gss error pipe write, don't return error
8ffe947 SUNRPC: Fix the return value in gss_import_sec_context()
e64b13f SUNRPC: Fix up an error return value in gss_import_sec_context_kerberos()
eb0b93d sunrpc: fix peername failed on closed listener
3aafc55 nfsd: make sure data is on disk before calling ->fsync
b7e5f77 Revert "x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium"
2448811 exofs: simple_write_end does not mark_inode_dirty
8dfabfc modules: Skip empty sections when exporting section notes
efd38f4 ASoC: fix params_rate() macro use in several codecs
e4dd8ca fasync: split 'fasync_helper()' into separate add/remove functions
1f51eb3 untangle the do_mremap() mess
c3a8e0e Linux 2.6.32.3
84d330e generic_permission: MAY_OPEN is not write access
3815270 rt2x00: Disable powersaving for rt61pci and rt2800pci.
8ac9e80 ksm: fix mlockfreed to munlocked
b2ea8cb vmscan: do not evict inactive pages when skipping an active list scan
370b758 lguest: fix bug in setting guest GDT entry
743c078 ext4: Update documentation to correct the inode_readahead_blks option name
fc31022 sched: Sched_rt_periodic_timer vs cpu hotplug
9127720 amd64_edac: fix forcing module load/unload
1538323 amd64_edac: make driver loading more robust
44a529c amd64_edac: fix driver instance freeing
2d9e1f0 x86, msr: msrs_alloc/free for CONFIG_SMP=n
eb21839 x86, msr: Add support for non-contiguous cpumasks
26eb2ac amd64_edac: unify MCGCTL ECC switching
ebd2802 cpumask: use modern cpumask style in drivers/edac/amd64_edac.c
a89a9e1 x86, msr: Unify rdmsr_on_cpus/wrmsr_on_cpus
b2dbc46 ext4: fix sleep inside spinlock issue with quota and dealloc (#14739)
dbe5cc0 ext4: Convert to generic reserved quota's space management.
bbf2450 quota: decouple fs reserved space from quota reservation
f07c88d Add unlocked version of inode_add_bytes() function
0aebc28 udf: Try harder when looking for VAT inode
3196f98 orinoco: fix GFP_KERNEL in orinoco_set_key with interrupts disabled
fad0c31 xen: wait up to 5 minutes for device connetion
2cfea00 xen: improvement to wait_for_devices()
af70ddf xen: fix is_disconnected_device/exists_disconnected_device
1dc51f1 S390: dasd: support DIAG access for read-only devices
4012cf6 drm: disable all the possible outputs/crtcs before entering KMS mode
08ff733 drm/radeon/kms: fix crtc vblank update for r600
a09adfe sched: Fix balance vs hotplug race
fb70ac4 Keys: KEYCTL_SESSION_TO_PARENT needs TIF_NOTIFY_RESUME architecture support
7fcb558 b43: avoid PPC fault during resume
a8e3ec9 hwmon: (sht15) Off-by-one error in array index + incorrect constants
048a424 netfilter: fix crashes in bridge netfilter caused by fragment jumps
89cf4f4 ipv6: reassembly: use seperate reassembly queues for conntrack and local delivery
ee6bfc6 e100: Fix broken cbs accounting due to missing memset.
ad46fed memcg: avoid oom-killing innocent task in case of use_hierarchy
b52d855 x86/ptrace: make genregs[32]_get/set more robust
6e2aa7d V4L/DVB (13596): ov511.c typo: lock => unlock
4b6d263 kernel/sysctl.c: fix the incomplete part of sysctl_max_map_count-should-be-non-negative.patch
3ec268a 'sysctl_max_map_count' should be non-negative
0399123 NOMMU: Optimise away the {dac_,}mmap_min_addr tests
1cfe005 mac80211: fix race with suspend and dynamic_ps_disable_work
14b4d74 iwlwifi: fix 40MHz operation setting on cards that do not allow it
c4ae8ae iwlwifi: fix more eeprom endian bugs
df5d119 iwlwifi: fix EEPROM/OTP reading endian annotations and a bug
0c0cdaf iwl3945: fix panic in iwl3945 driver
66c9e44 iwl3945: disable power save
87d512c ath9k_hw: Fix AR_GPIO_INPUT_EN_VAL_BT_PRIORITY_BB and its shift value in 0x4054
a6d8cc6 ath9k_hw: Fix possible OOB array indexing in gen_timer_index[] on 64-bit
12ba709 ath9k: fix suspend by waking device prior to stop
c965e1e ath9k: wake hardware during AMPDU TX actions
463a7f9 ath9k: fix missed error codes in the tx status check
bef82b6 ath9k: Fix TX queue draining
0ebbdd7 ath9k: wake hardware for interface IBSS/AP/Mesh removal
d5086b9 ath5k: fix SWI calibration interrupt storm
4777020 cfg80211: fix race between deauth and assoc response
9f7028e mac80211: Fix IBSS merge
0b41c5a mac80211: fix WMM AP settings application
330b937 mac80211: fix propagation of failed hardware reconfigurations
38cf2a0 iwmc3200wifi: fix array out-of-boundary access
08a9378 Libertas: fix buffer overflow in lbs_get_essid()
3b96f9a KVM: LAPIC: make sure IRR bitmap is scanned after vm load
3a9f992 KVM: MMU: remove prefault from invlpg handler
8b9f038 ioat2,3: put channel hardware in known state at init
e05a6f0 ioat3: fix p-disabled q-continuation
e93166f x86/amd-iommu: Fix initialization failure panic
cd7bc18 cifs: NULL out tcon, pSesInfo, and srvTcp pointers when chasing DFS referrals
6cb5fcc dma-debug: Fix bug causing build warning
120dbaa dma-debug: Do not add notifier when dma debugging is disabled.
c4ddbba dma: at_hdmac: correct incompatible type for argument 1 of 'spin_lock_bh'
ed8f6eb md: Fix unfortunate interaction with evms
acb8be4 x86: SGI UV: Fix writes to led registers on remote uv hubs
4ba51fe drivers/net/usb: Correct code taking the size of a pointer
526fed8 USB: fix bugs in usb_(de)authorize_device
c6d7a67 USB: rename usb_configure_device
f661c3f Bluetooth: Prevent ill-timed autosuspend in USB driver
b71bfa6 USB: musb: gadget_ep0: avoid SetupEnd interrupt
3635acd USB: Fix a bug on appledisplay.c regarding signedness
5a82dd5 USB: option: support hi speed for modem Haier CE100
702a0a0 USB: emi62: fix crash when trying to load EMI 6|2 firmware
2d67231 drm/radeon: fix build on 64-bit with some compilers.
474ae5e ASoC: Do not write to invalid registers on the wm9712.
d75621c powerpc: Handle VSX alignment faults correctly in little-endian mode
8aafd7d ACPI: Use the return result of ACPI lid notifier chain correctly
3872bf5 ACPI: EC: Fix MSI DMI detection
5ab8996 acerhdf: limit modalias matching to supported
296e9be ALSA: hda - Fix missing capsrc_nids for ALC88x
aec8dc2 sound: sgio2audio/pdaudiocf/usb-audio: initialize PCM buffer
e255d3c ASoC: wm8974: fix a wrong bit definition
1ee0552 pata_cmd64x: fix overclocking of UDMA0-2 modes
f31733a pata_hpt3x2n: fix clock turnaround
fa3f5a5 clockevents: Prevent clockevent_devices list corruption on cpu hotplug
8e04c81 sched: Select_task_rq_fair() must honour SD_LOAD_BALANCE
c9ac6a9 x86, cpuid: Add "volatile" to asm in native_cpuid()
14ae082 sched: Fix task_hot() test order
fdf2675 SCSI: fc class: fix fc_transport_init error handling
1ab0714 SCSI: st: fix mdata->page_order handling
9f63d27 SCSI: qla2xxx: dpc thread can execute before scsi host has been added
c1d17da SCSI: ipr: fix EEH recovery
a1092bf Linux 2.6.32.2

The problem has to be somewhere in there. Frank, you're the only guy up to now bringing up hard evidence and two relatively close good/bad kernel versions. Would you be able to dig deeper on this? It's just ridiculous some IO can prevent a quadcore from skipless video playback (on 2.6.34-git12 that is).. because of btrfs i can't switch back to 2.6.32.2 - but maybe someone can figure out how to use the phoronix-test-suite's automagic to bisect this?

And despite all noise: this bug really shouldn't be marked RESOLVED INSUFFICIENT_DATA ^^