Re: [PATCH 02/10] drm/i915: Add counters in the drm_dp_aux struct for I2C NACKs and DEFERs

Daniel Vetter
2014-11-04T22:26:12Z

On Tue, Nov 04, 2014 at 03:17:35PM -0700, Todd Previte wrote:
> These counters are used for Displayort compliance testing to detect error
> conditions when executing tests 4.2.2.4 and 4.2.2.5 in the Displayport Link
> CTS specificaiton. They determine whether to use the preferred/requested
> mode or the failsafe mode during these tests.
>
> V2:
> - Addressed previous review feedback
> - Updated commit message
> - Changed from uint8_t to uint32_t
>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Todd Previte <tprevite@gmail.com>
> ---
> drivers/gpu/drm/drm_dp_helper.c | 2 ++
> include/drm/drm_dp_helper.h | 1 +
> 2 files changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 08e33b8..8353051 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -654,10 +654,12 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
>
> case DP_AUX_I2C_REPLY_NACK:
> DRM_DEBUG_KMS("I2C nack\n");
> + aux->i2c_nack_count++;
> return -EREMOTEIO;
>
> case DP_AUX_I2C_REPLY_DEFER:
> DRM_DEBUG_KMS("I2C defer\n");
> + aux->i2c_defer_count++;
> usleep_range(400, 500);
> continue;
>
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 8edeed0..23082ce 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -551,6 +551,7 @@ struct drm_dp_aux {
> struct mutex hw_mutex;
> ssize_t (*transfer)(struct drm_dp_aux *aux,
> struct drm_dp_aux_msg *msg);
> + uint32_t i2c_nack_count, i2c_defer_count;

My reply missed your resend. I think unsigned instead of uint32_t has
clearer intent - at least nearyb driver code uint32_t usually means a
32bit hw register value. Which this isn't.

I've bikeshedded this and picked this up into my drm-misc tree.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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