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Commit 658ac4c6 authored by Damien Lespiau's avatar Damien Lespiau Committed by Daniel Vetter
Browse files

drm/i915: Disable display when fused off 



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 <mika.kuoppala@intel.com> (for v3)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (for v3)
Signed-off-by: default avatarDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 6e4930f6

drivers/gpu/drm/i915/i915_dma.c

+31 −1
Original line number Diff line number Diff line
@@ -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;

		}

	}

}



/**

drivers/gpu/drm/i915/i915_reg.h

+2 −0
Original line number Diff line number Diff line
@@ -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)