Comment 61 for bug 1492764

I am seeing this on a Dell E7240 (Haswell) freshly booted into 4.2. The issue was not seen on 4.1.2 or previous.

[ 2698.293746] [drm:check_crtc_state] *ERROR* mismatch in ips_enabled (expected 1, found 0)
[ 2698.293753] ------------[ cut here ]------------
[ 2698.293761] WARNING: CPU: 0 PID: 1833 at drivers/gpu/drm/i915/intel_display.c:12324 check_crtc_state+0x8ab/0xfd0()
[ 2698.293763] pipe state doesn't match!
[ 2698.293780] Modules linked in: fuse ctr ccm xt_addrtype xt_conntrack ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 iptable_filter ip_tables x_tables nf_nat nf_conntrack bridge stp llc dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c loop binfmt_misc bnep nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc arc4 nls_utf8 nls_cp437 vfat fat qmi_wwan uvcvideo videobuf2_vmalloc videobuf2_memops iwlmvm videobuf2_core cdc_mbim v4l2_common cdc_ncm cdc_wdm videodev usbnet mii mac80211 media snd_hda_codec_hdmi dell_smm_hwmon intel_rapl iosf_mbi x86_pkg_temp_thermal intel_powerclamp btusb snd_hda_codec_realtek snd_hda_codec_generic joydev iwlwifi btintel bluetooth pcspkr efivars i2c_i801 sg snd_hda_intel cfg80211 snd_hda_codec
[ 2698.293911] snd_hwdep snd_hda_core snd_pcm snd_timer tpm_tis 8250 serial_core evdev battery ac processor md_mod tpm_rng tpm rng_core efivarfs autofs4 btrfs xor raid6_pq algif_skcipher af_alg crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ehci_pci ehci_hcd sdhci_pci xhci_pci xhci_hcd thermal sdhci_acpi sdhci mmc_core i2c_hid hid jitterentropy_rng sha256_ssse3 sha256_generic hmac drbg ansi_cprng
[ 2698.293977] CPU: 0 PID: 1833 Comm: Xorg Not tainted 4.2.0 #1
[ 2698.293980] Hardware name: Dell Inc. Latitude E7240/07RPNV, BIOS A15 05/19/2015
[ 2698.293998] 0000000000000000 ffffffff819c26e0 ffffffff816898ee ffff8804030bf858
[ 2698.294004] ffffffff810b394c ffff8800d5ba9400 ffff88040c3d1000 ffff88040ab40000
[ 2698.294009] 0000000000000001 ffff88040c3d1350 ffffffff810b39c5 ffffffff819f0f1f
[ 2698.294015] Call Trace:
[ 2698.294024] [<ffffffff816898ee>] ? dump_stack+0x40/0x50
[ 2698.294048] [<ffffffff810b394c>] ? warn_slowpath_common+0x7c/0xb0
[ 2698.294054] [<ffffffff810b39c5>] ? warn_slowpath_fmt+0x45/0x50
[ 2698.294059] [<ffffffff8146563b>] ? check_crtc_state+0x8ab/0xfd0
[ 2698.294066] [<ffffffff81442c8b>] ? i915_get_crtc_scanoutpos+0x18b/0x230
[ 2698.294093] [<ffffffff81478116>] ? intel_modeset_check_state+0x206/0xb10
[ 2698.294101] [<ffffffff81479789>] ? intel_crtc_set_config+0x529/0x590
[ 2698.294108] [<ffffffff813f6367>] ? drm_crtc_check_viewport+0x27/0xe0
[ 2698.294130] [<ffffffff813f7bf9>] ? drm_mode_set_config_internal+0x59/0xf0
[ 2698.294137] [<ffffffff813fbabf>] ? drm_mode_setcrtc+0x17f/0x4d0
[ 2698.294143] [<ffffffff813edd1d>] ? drm_ioctl+0x16d/0x550
[ 2698.294151] [<ffffffffc024c930>] ? evdev_read+0xc0/0x2c0 [evdev]
[ 2698.294175] [<ffffffff811e794e>] ? do_vfs_ioctl+0x2be/0x490
[ 2698.294183] [<ffffffff810bd942>] ? recalc_sigpending+0x12/0x50
[ 2698.294189] [<ffffffff811e7b91>] ? SyS_ioctl+0x71/0x80
[ 2698.294194] [<ffffffff810c08d0>] ? SyS_rt_sigprocmask+0x60/0xa0
[ 2698.294217] [<ffffffff8168f817>] ? entry_SYSCALL_64_fastpath+0x12/0x6a
[ 2698.294221] ---[ end trace c252f4cf31b49867 ]---