linux-kernel - Re: [PATCH] drm: dpcd: Print more useful information during error

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Date:   Wed, 15 Apr 2020 21:44:58 -0400
From:   Aurabindo Pillai <mail@...abindo.in>
To:     Jani Nikula <jani.nikula@...ux.intel.com>
Cc:     maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm: dpcd: Print more useful information during error

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@...abindo.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@...ux.intel.com> wrote:
>
> On Thu, 09 Apr 2020, Aurabindo Pillai <mail@...abindo.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@...abindo.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