[Intel-gfx] [PATCH] drm/i915: Show debugfs dpcd read failure directly

[Jani Nikula]

On Fri, 20 Jul 2018, Rodrigo Vivi <rodrigo.vivi at intel.com> wrote:
> Instead of using a backchannel if some dpcd read failed we
> can show that directly on debugfs output.
>
> We are not returning an error because we might still want
> to know if sub-sequent reads works, but we shouldn't
> need to check 2 places to see why reg is not on the list.

Should we just nuke this debugfs and use the aux chardev interface to
dpcd instead?

BR,
Jani.

>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 59dc0610ea44..5d8da4e8c444 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -4846,8 +4846,8 @@ static int i915_dpcd_show(struct seq_file *m, void *data)
>  
>  		err = drm_dp_dpcd_read(&intel_dp->aux, b->offset, buf, size);
>  		if (err <= 0) {
> -			DRM_ERROR("dpcd read (%zu bytes at %u) failed (%zd)\n",
> -				  size, b->offset, err);
> +			seq_printf(m, "dpcd read (%zu bytes at %u) failed (%zd)\n",
> +				   size, b->offset, err);
>  			continue;
>  		}

-- 
Jani Nikula, Intel Open Source Graphics Center