Re: [PATCH v4 0/3] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Tokunori,

ikegami.t@gmail.com wrote on Thu, 17 Mar 2022 00:54:52 +0900:

> As pointed out by this bug report [1], buffered writes are now broken on
> S29GL064N. This issue comes from a rework which switched from using chip_good()
> to chip_ready(), because DQ true data 0xFF is read on S29GL064N and an error
> returned by chip_good(). One way to solve the issue is to revert the change
> partially to use chip_ready for S29GL064N.

Thanks for your quick iterations but overall I seriously don't feel
this series is ready. At least right now I am still not satisfied by
its shape.

> 
> [1] https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/
> 
> Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")

... and this Fixes tag points to a v4.18 kernel, so if this is true, we
should have a backport-able patch. This also means that this is not as
critical than I thought if people already lived 4 years with the bug.

Vignesh, I let you continue iterating with Tokunori and ack the series
when you feel it's ready.

> Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
> Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> Cc: stable@vger.kernel.org
> 
> Tokunori Ikegami (3):
>   mtd: cfi_cmdset_0002: Move and rename
>     chip_check/chip_ready/chip_good_for_write
>   mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N
>   mtd: cfi_cmdset_0002: Add S29GL064N ID definition
> 
>  drivers/mtd/chips/cfi_cmdset_0002.c | 93 +++++++++++++++--------------
>  1 file changed, 49 insertions(+), 44 deletions(-)
> 

Thanks,
Miquèl