Re: [PATCH 1/7] mfd: cros-ec: Fix host command buffer size

Lee Jones
2017-04-04T08:37:41Z

On Mon, 03 Apr 2017, Enric Balletbo i Serra wrote:

>
>
> On 03/04/17 16:30, Lee Jones wrote:
> > On Mon, 03 Apr 2017, Lee Jones wrote:
> >
> >> On Fri, 24 Mar 2017, Enric Balletbo i Serra wrote:
> >>
> >>> From: Vic Yang <victoryang@google.com>
> >>>
> >>> For SPI, we can get up to 32 additional bytes for response preamble.
> >>> The current overhead (2 bytes) may cause problems when we try to receive
> >>> a big response. Update it to 32 bytes.
> >>>
> >>> Without this fix we could see a kernel BUG when we receive a big response
> >>> from the Chrome EC when is connected via SPI.
> >>>
> >>> Signed-off-by: Vic Yang <victoryang@google.com>
> >>> Tested-by: Enric Balletbo i Serra <enric.balletbo.collabora.com>
> >>> ---
> >>>
> >>> This patch is a FIX, and I think that would be interesting see it merged
> >>> in this release cycle. This should go through the MFD tree and can be picked
> >>> independently of the other patches. Lee Jones I think this is for you.
> >>>
> >>> include/linux/mfd/cros_ec.h | 3 ++-
> >>> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> Applied, thanks.
> >
> > Scrap that, I'll keep it with the set.
> >
>
> Ok, I'll send a v2 asap with this patch and the few modifications requested on
> patch 7/7. I'm wondering though if this specific patch could go with current
> release cycle as (explained above) is a fix and current kernel is affected.

Yes, but please send it property next time.

I.e. On its own and with either a "Fixes:" tag or Cc stable.

If you don't know what I'm talking about look it up in Documentation.

> >>> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> >>> index b3e812f..3b16c90 100644
> >>> --- a/include/linux/mfd/cros_ec.h
> >>> +++ b/include/linux/mfd/cros_ec.h
> >>> @@ -35,10 +35,11 @@
> >>> * Max bus-specific overhead incurred by request/responses.
> >>> * I2C requires 1 additional byte for requests.
> >>> * I2C requires 2 additional bytes for responses.
> >>> + * SPI requires up to 32 additional bytes for responses.
> >>> * */
> >>> #define EC_PROTO_VERSION_UNKNOWN 0
> >>> #define EC_MAX_REQUEST_OVERHEAD 1
> >>> -#define EC_MAX_RESPONSE_OVERHEAD 2
> >>> +#define EC_MAX_RESPONSE_OVERHEAD 32
> >>>
> >>> /*
> >>> * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
> >>
> >

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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