Re: [PATCH v2] i2c: designware: Only check the first byte for SMBus block read length

[Jarkko Nikula]

On 6/16/20 6:43 PM, Sultan Alsawaf wrote:
> From: Sultan Alsawaf <sultan@xxxxxxxxxxxxxxx>
>
> SMBus block reads can be broken because the read function will just skip
> over bytes it doesn't like until reaching a byte that conforms to the
> length restrictions for block reads. This is problematic when it isn't
> known if the incoming payload is indeed a conforming block read.
>
> According to the SMBus specification, block reads will only send the
> payload length in the first byte, so we can fix this by only considering
> the first byte in a sequence for block read length purposes.
>
> Fixes: c3ae106050b9 ("i2c: designware: Implement support for SMBus block read and write")
> Signed-off-by: Sultan Alsawaf <sultan@xxxxxxxxxxxxxxx>
> ---
>   drivers/i2c/busses/i2c-designware-master.c | 16 +++++++---------
>   1 file changed, 7 insertions(+), 9 deletions(-)
Acked-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>