Re: [PATCH 2/2] drm/i915/dp: Use common error handling code in intel_dp_sink_crc_stop()

From: Jani Nikula
Date: Tue Oct 24 2017 - 12:13:57 EST


On Tue, 24 Oct 2017, SF Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx> wrote:
> From: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> Date: Tue, 24 Oct 2017 15:40:47 +0200
>
> Adjust jump targets so that a specific error code assignment
> will be in the implementation only at the end of this function.

This is not an issue that needs to be "fixed".

>
> This issue was detected by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 30 ++++++++++++++----------------
> 1 file changed, 14 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 342f1a1fa085..3dd514a77008 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3894,27 +3894,19 @@ static int intel_dp_sink_crc_stop(struct intel_dp *intel_dp)
> int count = 0;
> int attempts = 10;
>
> - if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK, &buf) < 0) {
> - DRM_DEBUG_KMS("Sink CRC couldn't be stopped properly\n");
> - ret = -EIO;
> - goto out;
> - }
> + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK, &buf) < 0)
> + goto report_failure;
>
> if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK,
> - buf & ~DP_TEST_SINK_START) < 0) {
> - DRM_DEBUG_KMS("Sink CRC couldn't be stopped properly\n");
> - ret = -EIO;
> - goto out;

I'd rather change the debug messages to distinguish the cases. I also
want to keep ret = -EIO in each individual branch, to distinguish from
the cases where it's set to something other than -EIO.

> - }
> + buf & ~DP_TEST_SINK_START) < 0)
> + goto report_failure;
>
> do {
> intel_wait_for_vblank(dev_priv, intel_crtc->pipe);
> + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf)
> + < 0)
> + goto e_io;
>
> - if (drm_dp_dpcd_readb(&intel_dp->aux,
> - DP_TEST_SINK_MISC, &buf) < 0) {
> - ret = -EIO;
> - goto out;
> - }

This is good as it is. The change makes it worse.

> count = buf & DP_TEST_COUNT_MASK;
> } while (--attempts && count);
>
> @@ -3923,9 +3915,15 @@ static int intel_dp_sink_crc_stop(struct intel_dp *intel_dp)
> ret = -ETIMEDOUT;
> }
>
> - out:
> +enable_ips:
> hsw_enable_ips(intel_crtc);
> return ret;
> +
> +report_failure:
> + DRM_DEBUG_KMS("Sink CRC couldn't be stopped properly\n");
> +e_io:
> + ret = -EIO;
> + goto enable_ips;

*shudder* Please no.

BR,
Jani.

> }
>
> static int intel_dp_sink_crc_start(struct intel_dp *intel_dp)

--
Jani Nikula, Intel Open Source Technology Center