[PATCH] drm/radeon: don't use fractional dividers on RS[78]80 if SS is enabled

[Alex Deucher]

On Mon, Jun 13, 2016 at 10:09 AM, Christian König
<deathsimple at vodafone.de> wrote:
> From: Christian König <christian.koenig at amd.com>
>
> Seems to cause problems for some older hardware. Kudos to Thom Kouwenhoven
> for working a lot with the PLLs and figuring this out.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>

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

Applied.  Thanks!

Alex

> ---
>  drivers/gpu/drm/radeon/atombios_crtc.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
> index bdc7b9e..482df5f 100644
> --- a/drivers/gpu/drm/radeon/atombios_crtc.c
> +++ b/drivers/gpu/drm/radeon/atombios_crtc.c
> @@ -589,7 +589,8 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
>                 if (ASIC_IS_DCE41(rdev) || ASIC_IS_DCE61(rdev) || ASIC_IS_DCE8(rdev))
>                         radeon_crtc->pll_flags |= RADEON_PLL_USE_FRAC_FB_DIV;
>                 /* use frac fb div on RS780/RS880 */
> -               if ((rdev->family == CHIP_RS780) || (rdev->family == CHIP_RS880))
> +               if (((rdev->family == CHIP_RS780) || (rdev->family == CHIP_RS880))
> +                   && !radeon_crtc->ss_enabled)
>                         radeon_crtc->pll_flags |= RADEON_PLL_USE_FRAC_FB_DIV;
>                 if (ASIC_IS_DCE32(rdev) && mode->clock > 165000)
>                         radeon_crtc->pll_flags |= RADEON_PLL_USE_FRAC_FB_DIV;
> @@ -626,7 +627,7 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
>                         if (radeon_crtc->ss.refdiv) {
>                                 radeon_crtc->pll_flags |= RADEON_PLL_USE_REF_DIV;
>                                 radeon_crtc->pll_reference_div = radeon_crtc->ss.refdiv;
> -                               if (ASIC_IS_AVIVO(rdev))
> +                               if (rdev->family >= CHIP_RV770)
>                                         radeon_crtc->pll_flags |= RADEON_PLL_USE_FRAC_FB_DIV;
>                         }
>                 }
> --
> 2.5.0
>