From 658ac4c6a29cfe7cedd494fb4b74acc3643dabab Mon Sep 17 00:00:00 2001 From: Damien Lespiau Date: Mon, 10 Feb 2014 17:19:45 +0000 Subject: [PATCH] drm/i915: Disable display when fused off MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit FUSE_STRAP has a bit to inform us that the display has been fused off. Use it to setup the definitive number of pipes at run-time. v2: actually tweak num_pipes, not num_planes v3: also tests SFUSE_STRAP bit 7 v4: rebase on top of drm-nightly use DRM_INFO() for the message telling display is fused off try to read the FUSE_LOCK bit to determine if PCH display is disabled v5: Don't read SFUSE_STRAP (register on the PCH) if num_pipes is already 0 from the initial device info struct (to prevent hangs) (Daniel Vetter) Reviewed-by: Mika Kuoppala (for v3) Reviewed-by: Ville Syrjälä (for v3) Signed-off-by: Damien Lespiau Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_dma.c | 32 +++++++++++++++++++++++++++++++- drivers/gpu/drm/i915/i915_reg.h | 2 ++ 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index e281298c6fd5..033c943b6bae 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -1466,16 +1466,46 @@ static void i915_dump_device_info(struct drm_i915_private *dev_priv) * - it's judged too laborious to fill n static structures with the limit * when a simple if statement does the job, * - run-time checks (eg read fuse/strap registers) are needed. + * + * This function needs to be called: + * - after the MMIO has been setup as we are reading registers, + * - after the PCH has been detected, + * - before the first usage of the fields it can tweak. */ static void intel_device_info_runtime_init(struct drm_device *dev) { + struct drm_i915_private *dev_priv = dev->dev_private; struct intel_device_info *info; - info = (struct intel_device_info *)&to_i915(dev)->info; + info = (struct intel_device_info *)&dev_priv->info; info->num_sprites = 1; if (IS_VALLEYVIEW(dev)) info->num_sprites = 2; + + if (info->num_pipes > 0 && + (INTEL_INFO(dev)->gen == 7 || INTEL_INFO(dev)->gen == 8) && + !IS_VALLEYVIEW(dev)) { + u32 fuse_strap = I915_READ(FUSE_STRAP); + u32 sfuse_strap = I915_READ(SFUSE_STRAP); + + /* + * SFUSE_STRAP is supposed to have a bit signalling the display + * is fused off. Unfortunately it seems that, at least in + * certain cases, fused off display means that PCH display + * reads don't land anywhere. In that case, we read 0s. + * + * On CPT/PPT, we can detect this case as SFUSE_STRAP_FUSE_LOCK + * should be set when taking over after the firmware. + */ + if (fuse_strap & ILK_INTERNAL_DISPLAY_DISABLE || + sfuse_strap & SFUSE_STRAP_DISPLAY_DISABLED || + (dev_priv->pch_type == PCH_CPT && + !(sfuse_strap & SFUSE_STRAP_FUSE_LOCK))) { + DRM_INFO("Display fused off, disabling\n"); + info->num_pipes = 0; + } + } } /** diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index ad044b7d12e6..fc03142e4ae7 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -5444,6 +5444,8 @@ /* SFUSE_STRAP */ #define SFUSE_STRAP 0xc2014 +#define SFUSE_STRAP_FUSE_LOCK (1<<13) +#define SFUSE_STRAP_DISPLAY_DISABLED (1<<7) #define SFUSE_STRAP_DDIB_DETECTED (1<<2) #define SFUSE_STRAP_DDIC_DETECTED (1<<1) #define SFUSE_STRAP_DDID_DETECTED (1<<0) -- 2.11.0