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Commit a3a8986c authored by Mahesh Kumar's avatar Mahesh Kumar Committed by Paulo Zanoni
Browse files

drm/i915/bxt: IPC WA for Broxton 



Display Workarounds #1135
If IPC is enabled in BXT, display underruns are observed.
WA: The Line Time programmed in the WM_LINETIME register should be
half of the actual calculated Line Time.

Programmed Line Time = 1/2*Calculated Line Time

Changes since V1:
 - Add Workaround number in commit & code
Changes since V2 (from Paulo):
 - Bikeshed white space and make the WA tag look like the others

Reviewed-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: default avatarMahesh Kumar <mahesh1.kumar@intel.com>
Signed-off-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161201154940.24446-3-mahesh1.kumar@intel.com
parent ef8a4fb4

drivers/gpu/drm/i915/i915_drv.c

+2 −0
Original line number Diff line number Diff line
@@ -1239,6 +1239,8 @@ int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent) 


	intel_runtime_pm_enable(dev_priv);



	dev_priv->ipc_enabled = false;



	/* Everything is in place, we can now relax! */

	DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",

		 driver.name, driver.major, driver.minor, driver.patchlevel,

drivers/gpu/drm/i915/i915_drv.h

+2 −0
Original line number Diff line number Diff line
@@ -2329,6 +2329,8 @@ struct drm_i915_private { 
	/* perform PHY state sanity checks? */

	bool chv_phy_assert[2];



	bool ipc_enabled;



	/* Used to save the pipe-to-encoder mapping for audio */

	struct intel_encoder *av_enc_map[I915_MAX_PIPES];

drivers/gpu/drm/i915/intel_pm.c

+11 −2
Original line number Diff line number Diff line
@@ -3761,7 +3761,10 @@ skl_compute_wm_level(const struct drm_i915_private *dev_priv, 
static uint32_t

skl_compute_linetime_wm(struct intel_crtc_state *cstate)

{

	struct drm_atomic_state *state = cstate->base.state;

	struct drm_i915_private *dev_priv = to_i915(state->dev);

	uint32_t pixel_rate;

	uint32_t linetime_wm;



	if (!cstate->base.active)

		return 0;
@@ -3771,8 +3774,14 @@ skl_compute_linetime_wm(struct intel_crtc_state *cstate) 
	if (WARN_ON(pixel_rate == 0))

		return 0;



	return DIV_ROUND_UP(8 * cstate->base.adjusted_mode.crtc_htotal * 1000,

			    pixel_rate);

	linetime_wm = DIV_ROUND_UP(8 * cstate->base.adjusted_mode.crtc_htotal *

				   1000, pixel_rate);



	/* Display WA #1135: bxt. */

	if (IS_BROXTON(dev_priv) && dev_priv->ipc_enabled)

		linetime_wm = DIV_ROUND_UP(linetime_wm, 2);



	return linetime_wm;

}



static void skl_compute_transition_wm(struct intel_crtc_state *cstate,