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drm/i915: Disable display when fused off

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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: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Damien Lespiau 2014-02-10 17:19:45 +00:00 committed by Daniel Vetter
parent 6e4930f6ee
commit 658ac4c6a2
2 changed files with 33 additions and 1 deletions
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32
drivers/gpu/drm/i915/i915_dma.c
View file

@ -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;
}
}
}
/**

2
drivers/gpu/drm/i915/i915_reg.h
View file

@ -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)