[PATCH v2 2/2] drm: fsl-dcu: enable PIXCLK on LS1021A

[Dmitry Baryshkov]

On Thu, Sep 26, 2024 at 04:09:03PM GMT, Alexander Stein wrote:
> Hi Dmitry,
> 
> Am Donnerstag, 26. September 2024, 08:05:56 CEST schrieb Dmitry Baryshkov:
> > On Thu, Sep 26, 2024 at 07:55:51AM GMT, Alexander Stein wrote:
> > > From: Matthias Schiffer <matthias.schiffer at tq-group.com>
> > > 
> > > The PIXCLK needs to be enabled in SCFG before accessing certain DCU
> > > registers, or the access will hang. For simplicity, the PIXCLK is enabled
> > > unconditionally, resulting in increased power consumption.
> > 
> > By this description it looks like a fix. What is the first broken
> > commit? It needs to be mentioned in the Fixes: tag. Or is it hat
> > existing devices have been enabling SCFG in some other way?
> 
> We discussed this internally and it seems this never worked, unless PIXCLK
> was already enabled in SCFG by a different way, e.g. firmware, etc.

My bet was on the firmware, but I never touched Layerscape platforms.
Anyway,

Fixes: 109eee2f2a18 ("drm/layerscape: Add Freescale DCU DRM driver")
Acked-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>


> 
> Best regards,
> Alexander
> 
> > > 
> > > Signed-off-by: Matthias Schiffer <matthias.schiffer at tq-group.com>
> > > Signed-off-by: Alexander Stein <alexander.stein at ew.tq-group.com>
> > > ---
> > > Changes in v2:
> > > * Add note about power consumption in commit message
> > > * Add note about power consumption in comment
> > > * Fix alignment
> > > 
> > 
> > 
> 
> 
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-- 
With best wishes
Dmitry