From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
PC8+ clobbers a bunch of displays registers which need to
be restored by hand or else we lost a bunch of workarounds.
The important ones for us are at least CHICKEN_PAR2* and
CHICKEN_PIPESL*.
Curiously at least some CHICKEN_PAR1* registers
are preserved by the hardware/firmware. Unfortunately Bspec
doens't really specify what gets clobbered vs. preserved
so further reverse engieering might be warranted to figure
out the specifics.
Note that PCH_LP_PARTITION_LEVEL_DISABLE is also set by
lpt_init_clock_gating() so the rmw in hsw_disable_pc8()
is now redundant. Remove it.
TODO: I suspect most gt stuff doesn't need this and we should
finish moving all of them from init_clock_gating() to
a more appropriate place...
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_display_power.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 5150069f3f82..83c44ec3f5ea 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -10,6 +10,7 @@
#include "i915_reg.h"
#include "intel_backlight_regs.h"
#include "intel_cdclk.h"
+#include "intel_clock_gating.h"
#include "intel_combo_phy.h"
#include "intel_de.h"
#include "intel_display_power.h"
@@ -1366,9 +1367,8 @@ static void hsw_disable_pc8(struct drm_i915_private *dev_priv)
hsw_restore_lcpll(dev_priv);
intel_init_pch_refclk(dev_priv);
- if (HAS_PCH_LPT_LP(dev_priv))
- intel_de_rmw(dev_priv, SOUTH_DSPCLK_GATE_D,
- 0, PCH_LP_PARTITION_LEVEL_DISABLE);
+ /* Many display registers don't survive PC8+ */
+ intel_clock_gating_init(dev_priv);
}
static void intel_pch_reset_handshake(struct drm_i915_private *dev_priv,
--
2.39.2
