[ARM] pflash_write: Unimplemented flash cmd sequence

[davidlt]

I find the bug already reported on qemu-devel mailing-list [1] w/o replies also on other sources.

Tested on Darwin (Mac OS X 10.7.5) and Scientific Linux 6.3 hosts. Also using the latest 1.2.X and 1.3.0-rc0 and qemu-linaro. On all host operating systems and with different versions on qemu results are the same.

I was following the official Ubuntu ARM instructions [2] how to test OS on ARM emulator.

oss: Could not initialize DAC
oss: Failed to open `/dev/dsp'
oss: Reason: No such file or directory
oss: Could not initialize DAC
oss: Failed to open `/dev/dsp'
oss: Reason: No such file or directory
audio: Failed to create voice `lm4549.out'
Uncompressing Linux................................................................................................................................................................................................. done, booting the kernel.
pflash_write: Unimplemented flash cmd sequence (offset 0000000000000000, wcycle 0x0 cmd 0x0 value 0xf000f0)
pflash_write: Unimplemented flash cmd sequence (offset 0000000000000000, wcycle 0x0 cmd 0x0 value 0xf0)

And it freezes, but still eats 40-50% of CPU core.

## Instructions ##

wget -c http://w3.impa.br/~gabrield/data/ubuntu-arm-development-rootfs.tar.bz2
tar jxfv ubuntu-arm-development-rootfs.tar.bz2
chmod +x run.sh
./run.sh

The user to login is ubuntu and password temppwd.

More details on [2].

- - -
[1] http://lists.gnu.org/archive/html/qemu-devel/2012-11/msg00863.html
[2] https://wiki.ubuntu.com/ARM/RootfsFromScratch

[Stefan Weil (ubuntu-weilnetz)]

The message from pflash_write is a warning which only says that the Intel flash emulation
got a command sequence which is only supported by the AMD flash emulation.

This warning is currently normal when Linux kernels try to determine the flash type.
Linux tries AMD before Intel.

So if there is any problem, it is not related to the flash emulation.

The test scenario works without any problem on a Debian Linux host
(tested up to the boot prompt).

Note that there are three location where you get output:
* stdout / stderr on the console
* serial output from the emulation (Alt-Ctrl-3 in QEMU SDL window)
* framebuffer output from the emulation (Alt-Ctrl-1 in QEMU SDL window)

It takes some time until the kernel sends output to the framebuffer (therefore 50 % cpu load),
but it works.

[Peter Maydell (pmaydell)]

We could drop it to a LOG_UNIMP/LOG_GUEST_ERROR qemu_log warning instead of a plain printf, I guess.

[Peter Maydell (pmaydell)]

As of commit 5928023c these pflash_cfi01 messages are now suppressed, so this bug will be fixed in the next release of QEMU (1.4.0) and qemu-linaro (2012.03).