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Commit 8ac5a6d5 authored by Sean Paul's avatar Sean Paul Committed by Daniel Vetter
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drm/i915: Don't lock panel registers when downclocking 



This patch replaces the locking from the downclock routines with an assert
to ensure the registers are indeed unlocked. Without this patch, pre-SNB
devices would lock the registers when downclocking which would cause a
WARNING on suspend/resume with downclocking enabled.

Note: To hit this bug, you need to have lvds downclocking enabled.

Signed-off-by: default avatarSean Paul <seanpaul@chromium.org>
Acked-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent d3ae0810

drivers/gpu/drm/i915/intel_display.c

+2 −12
Original line number Diff line number Diff line
@@ -7006,9 +7006,7 @@ static void intel_increase_pllclock(struct drm_crtc *crtc) 
	if (!HAS_PIPE_CXSR(dev) && (dpll & DISPLAY_RATE_SELECT_FPA1)) {

		DRM_DEBUG_DRIVER("upclocking LVDS\n");



		/* Unlock panel regs */

		I915_WRITE(PP_CONTROL,

			   I915_READ(PP_CONTROL) | PANEL_UNLOCK_REGS);

		assert_panel_unlocked(dev_priv, pipe);



		dpll &= ~DISPLAY_RATE_SELECT_FPA1;

		I915_WRITE(dpll_reg, dpll);
@@ -7017,9 +7015,6 @@ static void intel_increase_pllclock(struct drm_crtc *crtc) 
		dpll = I915_READ(dpll_reg);

		if (dpll & DISPLAY_RATE_SELECT_FPA1)

			DRM_DEBUG_DRIVER("failed to upclock LVDS!\n");



		/* ...and lock them again */

		I915_WRITE(PP_CONTROL, I915_READ(PP_CONTROL) & 0x3);

	}



	/* Schedule downclock */
@@ -7049,9 +7044,7 @@ static void intel_decrease_pllclock(struct drm_crtc *crtc) 
	if (!HAS_PIPE_CXSR(dev) && intel_crtc->lowfreq_avail) {

		DRM_DEBUG_DRIVER("downclocking LVDS\n");



		/* Unlock panel regs */

		I915_WRITE(PP_CONTROL, I915_READ(PP_CONTROL) |

			   PANEL_UNLOCK_REGS);

		assert_panel_unlocked(dev_priv, pipe);



		dpll |= DISPLAY_RATE_SELECT_FPA1;

		I915_WRITE(dpll_reg, dpll);
@@ -7059,9 +7052,6 @@ static void intel_decrease_pllclock(struct drm_crtc *crtc) 
		dpll = I915_READ(dpll_reg);

		if (!(dpll & DISPLAY_RATE_SELECT_FPA1))

			DRM_DEBUG_DRIVER("failed to downclock LVDS!\n");



		/* ...and lock them again */

		I915_WRITE(PP_CONTROL, I915_READ(PP_CONTROL) & 0x3);

	}



}