From a3a8986cb22aafd83681b7e783ca6d4963712989 Mon Sep 17 00:00:00 2001 From: Mahesh Kumar Date: Thu, 1 Dec 2016 21:19:34 +0530 Subject: [PATCH] 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: Paulo Zanoni Signed-off-by: Mahesh Kumar Signed-off-by: Paulo Zanoni Link: http://patchwork.freedesktop.org/patch/msgid/20161201154940.24446-3-mahesh1.kumar@intel.com --- drivers/gpu/drm/i915/i915_drv.c | 2 ++ drivers/gpu/drm/i915/i915_drv.h | 2 ++ drivers/gpu/drm/i915/intel_pm.c | 13 +++++++++++-- 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 5fe27e42d81b..d2cc28f6953d 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -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, diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 33758ac5ec9a..4eea9255dc53 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -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]; diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 4db68459fd18..9ea3eeed3385 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -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, -- 2.20.1