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drm/i915: write D_COMP using the mailbox

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You can't write it using the MCHBAR mirror, the write will just get
dropped.

This should make us BSpec-compliant, but there's no real bug I could
reproduce that is fixed by this patch.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Fix spelling mistake in the comment that Damien spotted.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Paulo Zanoni 2013-09-10 19:36:37 -03:00 committed by Daniel Vetter
parent 507c1a4548
commit 515b239269
2 changed files with 12 additions and 2 deletions
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4
drivers/gpu/drm/i915/i915_reg.h
View file

@ -1441,6 +1441,8 @@
* device 0 function 0's pci config register 0x44 or 0x48 and matches it in
* every way. It is not accessible from the CP register read instructions.
*
* Starting from Haswell, you can't write registers using the MCHBAR mirror,
* just read.
*/
#define MCHBAR_MIRROR_BASE 0x10000
@ -4724,6 +4726,8 @@
#define GEN6_PCODE_READ_MIN_FREQ_TABLE 0x9
#define GEN6_PCODE_WRITE_RC6VIDS 0x4
#define GEN6_PCODE_READ_RC6VIDS 0x5
#define GEN6_PCODE_READ_D_COMP 0x10
#define GEN6_PCODE_WRITE_D_COMP 0x11
#define GEN6_ENCODE_RC6_VID(mv) (((mv) - 245) / 5)
#define GEN6_DECODE_RC6_VID(vids) (((vids) * 5) + 245)
#define GEN6_PCODE_DATA 0x138128

10
drivers/gpu/drm/i915/intel_display.c
View file

@ -6140,7 +6140,10 @@ void hsw_disable_lcpll(struct drm_i915_private *dev_priv,
val = I915_READ(D_COMP);
val |= D_COMP_COMP_DISABLE;
I915_WRITE(D_COMP, val);
mutex_lock(&dev_priv->rps.hw_lock);
if (sandybridge_pcode_write(dev_priv, GEN6_PCODE_WRITE_D_COMP, val))
DRM_ERROR("Failed to disable D_COMP\n");
mutex_unlock(&dev_priv->rps.hw_lock);
POSTING_READ(D_COMP);
ndelay(100);
@ -6182,7 +6185,10 @@ void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
val = I915_READ(D_COMP);
val |= D_COMP_COMP_FORCE;
val &= ~D_COMP_COMP_DISABLE;
I915_WRITE(D_COMP, val);
mutex_lock(&dev_priv->rps.hw_lock);
if (sandybridge_pcode_write(dev_priv, GEN6_PCODE_WRITE_D_COMP, val))
DRM_ERROR("Failed to enable D_COMP\n");
mutex_unlock(&dev_priv->rps.hw_lock);
POSTING_READ(D_COMP);
val = I915_READ(LCPLL_CTL);