[Intel-gfx] [PATCH 8/8] drm/edid: Dump bogus 18 byte descriptors

[Alex Deucher]

On Fri, Jan 24, 2020 at 3:03 PM Ville Syrjala
<ville.syrjala at linux.intel.com> wrote:
>
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> I'm curious if there are any bogus 18 byte descriptors around.
> Let's dump them out if we encounter them.
>
> Not sure we'd actually want this, but at least I get to see
> if our CI has anything that hits this :)
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Acked-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/drm_edid.c | 22 +++++++++++++++++++---
>  1 file changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 8e76efe1654d..4d8303e56536 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2202,6 +2202,12 @@ static bool is_display_descriptor(const u8 d[18], u8 tag)
>                 d[2] == 0x00 && d[3] == tag;
>  }
>
> +static bool is_any_display_descriptor(const u8 d[18])
> +{
> +       return d[0] == 0x00 && d[1] == 0x00 &&
> +               d[2] == 0x00;
> +}
> +
>  static bool is_detailed_timing_descriptor(const u8 d[18])
>  {
>         return d[0] != 0x00 || d[1] != 0x00;
> @@ -2209,6 +2215,15 @@ static bool is_detailed_timing_descriptor(const u8 d[18])
>
>  typedef void detailed_cb(const struct detailed_timing *timing, void *closure);
>
> +static void do_detailed_block(const u8 d[18], detailed_cb *cb, void *closure)
> +{
> +       if (!is_detailed_timing_descriptor(d) &&
> +           !is_any_display_descriptor(d))
> +               DRM_WARN("Unrecognized 18 byte descriptor: %*ph\n", 18, d);
> +
> +       cb((const struct detailed_timing *)d, closure);
> +}
> +
>  static void
>  cea_for_each_detailed_block(const u8 *ext, detailed_cb *cb, void *closure)
>  {
> @@ -2221,7 +2236,7 @@ cea_for_each_detailed_block(const u8 *ext, detailed_cb *cb, void *closure)
>
>         n = (127 - d) / 18;
>         for (i = 0; i < n; i++)
> -               cb((const struct detailed_timing *)(det_base + 18 * i), closure);
> +               do_detailed_block(det_base + 18 * i, cb, closure);
>  }
>
>  static void
> @@ -2234,7 +2249,7 @@ vtb_for_each_detailed_block(const u8 *ext, detailed_cb *cb, void *closure)
>                 return; /* unknown version */
>
>         for (i = 0; i < n; i++)
> -               cb((const struct detailed_timing *)(det_base + 18 * i), closure);
> +               do_detailed_block(det_base + 18 * i, cb, closure);
>  }
>
>  static void
> @@ -2247,7 +2262,8 @@ drm_for_each_detailed_block(const u8 *raw_edid, detailed_cb *cb, void *closure)
>                 return;
>
>         for (i = 0; i < EDID_DETAILED_TIMINGS; i++)
> -               cb(&(edid->detailed_timings[i]), closure);
> +               do_detailed_block((const u8 *)&edid->detailed_timings[i],
> +                                 cb, closure);
>
>         for (i = 1; i <= raw_edid[0x7e]; i++) {
>                 const u8 *ext = raw_edid + (i * EDID_LENGTH);
> --
> 2.24.1
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel