Re: [PATCH] omapfb: dss: Fix max fclk divider for omap36xx

From: Sam Ravnborg
Date: Fri Jul 03 2020 - 15:36:57 EST


Hi Tomi.

On Fri, Jul 03, 2020 at 10:17:29AM +0300, Tomi Valkeinen wrote:
> On 30/06/2020 21:26, Adam Ford wrote:
> > The drm/omap driver was fixed to correct an issue where using a
> > divider of 32 breaks the DSS despite the TRM stating 32 is a valid
> > number. Through experimentation, it appears that 31 works, and
> > it is consistent with the value used by the drm/omap driver.
> >
> > This patch fixes the divider for fbdev driver instead of the drm.
> >
> > Fixes: f76ee892a99e ("omapfb: copy omapdss & displays for omapfb")
> >
> > Cc: <stable@xxxxxxxxxxxxxxx> #4.9+
> > Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
> > ---
> > Linux 4.4 will need a similar patch, but it doesn't apply cleanly.
> >
> > The DRM version of this same fix is:
> > e2c4ed148cf3 ("drm/omap: fix max fclk divider for omap36xx")
> >
> >
> > diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > index 7252d22dd117..bfc5c4c5a26a 100644
> > --- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > +++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > @@ -833,7 +833,7 @@ static const struct dss_features omap34xx_dss_feats = {
> > };
> > static const struct dss_features omap3630_dss_feats = {
> > - .fck_div_max = 32,
> > + .fck_div_max = 31,
> > .dss_fck_multiplier = 1,
> > .parent_clk_name = "dpll4_ck",
> > .dpi_select_source = &dss_dpi_select_source_omap2_omap3,
> >
>
> Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Will you apply to drm-misc?

Note following output from "dim fixes":
$ dim fixes f76ee892a99e
Fixes: f76ee892a99e ("omapfb: copy omapdss & displays for omapfb")
Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxx>
Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Cc: Jason Yan <yanaijie@xxxxxxxxxx>
Cc: "Andrew F. Davis" <afd@xxxxxx>
Cc: YueHaibing <yuehaibing@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.5+

Here it says the fix is valid from v4.5 onwards.

Sam
>
> Tomi
>
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