The Sharp LQ116M1JW105 reports that it supports 8 bpc modes,
but it will happen display noise in some videos.
So, limit it to 6 bpc modes.

Signed-off-by: Ajye Huang <ajye_huang@compal.corp-partner.google.com>
---
changes from v1->v2:
* Change EDID_QUIRK_FORCE_6BPC to BIT(EDID_QUIRK_FORCE_6BPC)

 drivers/gpu/drm/drm_edid.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index e2e85345aa9a..26bb7710a462 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -250,6 +250,9 @@ static const struct edid_quirk {
 	EDID_QUIRK('S', 'V', 'R', 0x1019, BIT(EDID_QUIRK_NON_DESKTOP)),
 	EDID_QUIRK('A', 'U', 'O', 0x1111, BIT(EDID_QUIRK_NON_DESKTOP)),
 
+	/* LQ116M1JW10 displays noise when 8 bpc, but display fine as 6 bpc */
+	EDID_QUIRK('S', 'H', 'P', 0x154c, BIT(EDID_QUIRK_FORCE_6BPC)),
+
 	/*
 	 * @drm_edid_internal_quirk entries end here, following with the
 	 * @drm_edid_quirk entries.
-- 
2.25.1

Hi,

On Fri, Oct 31, 2025 at 9:01 PM Ajye Huang
<ajye_huang@compal.corp-partner.google.com> wrote:
>
> The Sharp LQ116M1JW105 reports that it supports 8 bpc modes,
> but it will happen display noise in some videos.
> So, limit it to 6 bpc modes.
>
> Signed-off-by: Ajye Huang <ajye_huang@compal.corp-partner.google.com>
> ---
> changes from v1->v2:
> * Change EDID_QUIRK_FORCE_6BPC to BIT(EDID_QUIRK_FORCE_6BPC)
>
>  drivers/gpu/drm/drm_edid.c | 3 +++
>  1 file changed, 3 insertions(+)

There was some extra testing and summarization on the internal
discussion about this problem that cleared up my confusion and I agree
that this is the right fix. While the panel does properly link train
at 8bpp and generally displays images OK, showing certain images on
the screen displays consistent corruption on just this panel (other
8bpp panels are fine). It seems like there's some sort of subtle bug
in the panel at 8bpp. Limiting it to 6bpp, which is what the panel was
originally tested with, is the right thing to do.

Reviewed-by: Douglas Anderson <dianders@chromium.org>

Hi,

On Mon, Nov 3, 2025 at 8:38 AM Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Fri, Oct 31, 2025 at 9:01 PM Ajye Huang
> <ajye_huang@compal.corp-partner.google.com> wrote:
> >
> > The Sharp LQ116M1JW105 reports that it supports 8 bpc modes,
> > but it will happen display noise in some videos.
> > So, limit it to 6 bpc modes.
> >
> > Signed-off-by: Ajye Huang <ajye_huang@compal.corp-partner.google.com>
> > ---
> > changes from v1->v2:
> > * Change EDID_QUIRK_FORCE_6BPC to BIT(EDID_QUIRK_FORCE_6BPC)
> >
> >  drivers/gpu/drm/drm_edid.c | 3 +++
> >  1 file changed, 3 insertions(+)
>
> There was some extra testing and summarization on the internal
> discussion about this problem that cleared up my confusion and I agree
> that this is the right fix. While the panel does properly link train
> at 8bpp and generally displays images OK, showing certain images on
> the screen displays consistent corruption on just this panel (other
> 8bpp panels are fine). It seems like there's some sort of subtle bug
> in the panel at 8bpp. Limiting it to 6bpp, which is what the panel was
> originally tested with, is the right thing to do.
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>

Pushed to drm-misc-next:

[1/1] drm/edid: add 6 bpc quirk to the Sharp LQ116M1JW10
      commit: f23e40e378a0858da26e8d5a6f09f82ecd95e247