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From:   Aurabindo Pillai <mail@aurabindo.in>
Date:   Wed, 15 Apr 2020 21:44:58 -0400
Message-ID: <CAMu4TMtb9f_zusEkUkDWzJMJ-uu8yciUUWxGybv2f4a+ER7B+Q@mail.gmail.com>
Subject: Re: [PATCH] drm: dpcd: Print more useful information during error
To:     Jani Nikula <jani.nikula@linux.intel.com>
Cc:     maarten.lankhorst@linux.intel.com, mripard@kernel.org,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org
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When DPCD access errors occur, knowing the register and request
associated with the error helps debugging, so print the
details in the debug message.

Signed-off-by: Aurabindo Pillai <mail@aurabindo.in>
---
 drivers/gpu/drm/drm_dp_helper.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index c6fbe6e6b..8aafc01f5 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -257,7 +257,9 @@ static int drm_dp_dpcd_access(struct drm_dp_aux
*aux, u8 request,
                        err = ret;
        }

-       DRM_DEBUG_KMS("Too many retries, giving up. First error: %d\n", err);
+       DRM_DEBUG_KMS("dpcd: Too many retries, giving up. First error: %d,"
+                     " address: 0x%x, request: 0x%x, size:%zu\n",
+                     err, msg.address, msg.request, msg.size);
        ret = err;

 unlock:
--
2.26.0

On Tue, Apr 14, 2020 at 7:04 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Thu, 09 Apr 2020, Aurabindo Pillai <mail@aurabindo.in> wrote:
> > When DPCD access errors occur, knowing the register and request
> > associated with the error helps debugging, so print the
> > details in the debug message.
> >
> > Signed-off-by: Aurabindo Pillai <mail@aurabindo.in>
> > ---
> >  drivers/gpu/drm/drm_dp_helper.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> > index a5364b519..545606aac 100644
> > --- a/drivers/gpu/drm/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/drm_dp_helper.c
> > @@ -257,7 +257,9 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
> >                       err = ret;
> >       }
> >
> > -     DRM_DEBUG_KMS("Too many retries, giving up. First error: %d\n", err);
> > +     DRM_DEBUG_KMS("dpcd: Too many retries, giving up. First error: %d\t"
> > +                   "address: %x\trequest: %x\t size:%zu\n",
> > +                   err, msg.address, msg.request, msg.size);
>
> Nitpicks, please don't add tabs, maybe use commas instead, and please
> add 0x in front of hex.
>
> BR,
> Jani.
>
>
> >       ret = err;
> >
> >  unlock:
>
> --
> Jani Nikula, Intel Open Source Graphics Center


-- 

Thanks and Regards,

Aurabindo J Pillai
https://aurabindo.in