Re: Mobility Radeon HD 4530/4570/545v: flicker in 1920x1080

[Christian KÃnig]

On 04.11.2015 00:03, Pavel Machek wrote:
> Hi!
>
>
> > > > > > > Any ideas?
> > > > > > Alex probably knows more about this, but it sounds like problems with
> > > > > > switching the memory clocks on 3D load.
> > > > > > Try to disable power management completely with radeon.dpm=0 on the kernel
> > > > > > command line or nailing the hardware at a specific power level using
> > > > > > sysfs.
> > > > > I tried that, but it still flickers.
> > > > It's probably pll stability.  There seem to be a number of regressions
> > > > since the pll code was rewritten to support matching the hdmi clocks
> > > > more closely.  Does this patch help?
> > > >
> > > > diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c
> > > > b/drivers/gpu/drm/radeon/atombios_crtc.c
> > > > index dac78ad..b86f06a 100644
> > > > --- a/drivers/gpu/drm/radeon/atombios_crtc.c
> > > > +++ b/drivers/gpu/drm/radeon/atombios_crtc.c
> > > > @@ -569,6 +569,8 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
> > > >          radeon_crtc->pll_flags = 0;
> > > >
> > > >          if (ASIC_IS_AVIVO(rdev)) {
> > > > +               radeon_crtc->pll_flags |= RADEON_PLL_PREFER_MINM_OVER_MAXP;
> > > > +
> > > >                  if ((rdev->family == CHIP_RS600) ||
> > > >                      (rdev->family == CHIP_RS690) ||
> > > >                      (rdev->family == CHIP_RS740))
> > > Help.. maybe... it is tricky to tell. It definitely does _not_ fix the
> > > issue completely.
> > You could also try the old pll algorithm:
> I reverted the patch above, and switched to the old algorithm.
>
> The flicker is still there. (But maybe its less horrible, like with
> RADEON_PLL_PREFER_MINM_OVER_MAXP).

The flickering would vanish completely if that's the reason for the 
issue you are seeing.

Try setting ref_div_min and ref_div_max to 2 in radeon_compute_pll_avivo().

But I'm not 100% convinced that this is actually a PLL problem, try to 
compile the firmware it complains about into the kernel as well.

Regards,
Christian.

> Thanks,
> 								Pavel
> 								

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