drm/radeon: fix PLLs on RS880 and older v2
This is a workaround for RS880 and older chips which seem to have
an additional limit on the minimum PLL input frequency.
v2: fix signed/unsigned warning
bugs:
https://bugzilla.kernel.org/show_bug.cgi?id=91861
https://bugzilla.kernel.org/show_bug.cgi?id=83461
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 1021169..913fafa 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -960,6 +960,9 @@
if (pll->flags & RADEON_PLL_USE_FRAC_FB_DIV &&
pll->flags & RADEON_PLL_USE_REF_DIV)
ref_div_max = pll->reference_div;
+ else if (pll->flags & RADEON_PLL_PREFER_MINM_OVER_MAXP)
+ /* fix for problems on RS880 */
+ ref_div_max = min(pll->max_ref_div, 7u);
else
ref_div_max = pll->max_ref_div;