[Lager(H2)-V4.10-rc2]: QSPI-FLASH: Warning message happened when writing a data file to SPI-FLASH

[Cyrille Pitchen]

Hi all,

Le 24/01/2017 à 08:43, Geert Uytterhoeven a écrit :
> CC linux-mtd
> 
> On Tue, Jan 24, 2017 at 7:34 AM, DongCV <cv-dong at jinso.co.jp> wrote:
>> Dear Michal,
>> Cc: Geert,
>>
>> I've tested the linux v4.10-rc2 for Gen2 Lager and found an issues when
>> writing data to SPI-FLASH with jffs2 format
>>
>> "root at linaro-naro:~# cp test.dat /mnt/media
>> [  223.874078] ------------[ cut here ]------------
>> [  223.888017] WARNING: CPU: 2 PID: 2008 at
>> drivers/mtd/spi-nor/spi-nor.c:1182 spi_nor_write+0x84/0x160
>> [  223.915507] Writing at offset 12 into a NOR page. Writing partial pages
>> may decrease reliability and increase wear of NOR flash.
>> [  223.915543] CPU: 2 PID: 2008 Comm: cp Not tainted 4.10.0-rc2-dirty #166
>> [  223.970037] Hardware name: Generic R8A7790 (Flattened Device Tree)
>> [  223.988563] Backtrace:
>> [  223.995934] [<c010a8a0>] (dump_backtrace) from [<c010aad8>]
>> (show_stack+0x18/0x1c)
>> [  224.018639]  r6:c04786f0 r5:00000000 r4:600f0013 r3:00404000
>> [  224.035626] [<c010aac0>] (show_stack) from [<c033b154>]
>> (dump_stack+0x80/0xa0)
>> [  224.057294] [<c033b0d4>] (dump_stack) from [<c011e49c>]
>> (__warn+0xd4/0x104)
>> [  224.078169]  r5:00000000 r4:ef203ba8
>> [  224.088894] [<c011e3c8>] (__warn) from [<c011e50c>]
>> (warn_slowpath_fmt+0x40/0x48)
>> [  224.111337]  r9:c0a2a6cb r8:ef203c8c r7:0000000c r6:00000000 r5:00000000
>> r4:eebfa418
>> [  224.134564] [<c011e4d0>] (warn_slowpath_fmt) from [<c04786f0>]
>> (spi_nor_write+0x84/0x160)
>> ..."
>>
>> Please have a look at the attached testlog file for detail.
> 
> I didn't keep the attachment, the test just does
> 
> # flash_erase -j /dev/mtd2 0 0
> # mount -t jffs2 /dev/mtdblock2 /mnt/media
> # dd if=/dev/mtdblock2 of=test.dat bs=512 count=1
> # cp test.dat /mnt/media
> 
>> And I found the patch which I think it is the cause of this issues.
>> The commit name is 'e5d05cb mtd: spi-nor: simplify write loop'
>> If I reverted this patch and retested it on H2 board, the issue will be
>> gone!
>

This is a known issue fixed by the patch "mtd: spi-nor: remove WARN_ONCE()
message in spi_nor_write()", which is planned to be mainlined in 4.11.

This patch only removes the WARN_ONCE() introduced by commit e5d05cb ("mtd:
spi-nor: simplify write loop"). All other modifications of commit e5d05cb
are fine and can be kept. It's only the WARN_ONCE() message that is
annoying and not so relevant.

So don't worry about this (false) warning and sorry for the noise!

Best regards,

Cyrille

> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
> 
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