Re: chrome-platform/for-kernelci bisection: baseline.bootrr.rockchip-dp-probed on rk3399-gru-kevin

[Guenter Roeck]

On 7/8/20 11:59 AM, kernelci.org bot wrote:
> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> * This automated bisection report was sent to you on the basis  *
> * that you may be involved with the breaking commit it has      *
> * found.  No manual investigation has been done to verify it,   *
> * and the root cause of the problem may be somewhere else.      *
> *                                                               *
> * If you do send a fix, please include this trailer:            *
> *   Reported-by: "kernelci.org bot" <bot@xxxxxxxxxxxx>          *
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> 
> chrome-platform/for-kernelci bisection: baseline.bootrr.rockchip-dp-probed on rk3399-gru-kevin
> 
> Summary:
>   Start:      154353417996 KERNELCI: x86_64_defconfig: Enable support for Chromebooks devices
>   Plain log:  https://storage.kernelci.org/chrome-platform/for-kernelci/v5.8-rc1-20-g154353417996/arm64/defconfig/gcc-8/lab-collabora/baseline-rk3399-gru-kevin.txt
>   HTML log:   https://storage.kernelci.org/chrome-platform/for-kernelci/v5.8-rc1-20-g154353417996/arm64/defconfig/gcc-8/lab-collabora/baseline-rk3399-gru-kevin.html
>   Result:     8c9a6ef40bf4 platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
> 
> Checks:
>   revert:     PASS
>   verify:     PASS
> 
> Parameters:
>   Tree:       chrome-platform
>   URL:        https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git
>   Branch:     for-kernelci
>   Target:     rk3399-gru-kevin
>   CPU arch:   arm64
>   Lab:        lab-collabora
>   Compiler:   gcc-8
>   Config:     defconfig
>   Test case:  baseline.bootrr.rockchip-dp-probed
> 
> Breaking commit found:
> 
> -------------------------------------------------------------------------------
> commit 8c9a6ef40bf400c64c9907031bd32b59f9d4aea2
> Author: Guenter Roeck <linux@xxxxxxxxxxxx>
> Date:   Sat Jul 4 07:26:07 2020 -0700
> 
>     platform/chrome: cros_ec_proto: Convert EC error codes to Linux error codes
>     
>     The EC reports a variety of error codes. Most of those, with the exception
>     of EC_RES_INVALID_VERSION, are converted to -EPROTO. As result, the actual
>     error code gets lost. Convert all EC errors to Linux error codes to report
>     a more meaningful error to the caller to aid debugging.
>     
>     Cc: Yu-Hsuan Hsu <yuhsuan@xxxxxxxxxxxx>
>     Cc: Prashant Malani <pmalani@xxxxxxxxxxxx>
>     Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>     Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> 

So, just FTR, turns out that there are callers which specifically check for
-EPROTO and examine the EC error code if it is returned, or just accept
-EPROTO as generic failure (but nothing else). Example is drivers/pwm/pwm-cros-ec.c:
cros_ec_num_pwms(). Such commands now fail, in this case because
EC_RES_INVALID_PARAM is now returned as -EINVAL and cros_ec_num_pwms()
doesn't expect that.

drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c has a similar problem;
it only accepts -EPROTO as "valid" error, but nothing else. I didn't check
for others.

Guenter