Ville Syrjälä ce35255032 drm/i915: Fix unclaimed register access due to delayed VGA memory disable ... VGA registers live inside the power well on HSW, so in order to write the VGA MSR register we need the power well to be on. We really must write to the register to properly clear the VGA_MSR_MEM_EN enable bit, even if all VGA registers get zeroed when the power well is down. It seems that the implicit zeroing done by the power well is not enough to propagate the VGA_MSR_MEM_EN bit to whomever is actually responsible for the memory decode ranges. If we leave VGA memory decode enabled, and then turn off the power well, all VGA memory reads will return zeroes. But if we first disable VGA memory deocde and then turn off the power well, VGA memory reads return all ones, indicating that the access wasn't claimed by anyone. For the vga arbiter to function correctly the IGD must not claim the VGA memory accesses. Previously we were doing the VGA_MSR register access while the power well was excplicitly powered up during driver init. But ever since commit 6e1b4fdad5 Author: Ville Syrjälä <ville.syrjala@linux.intel.com> Date: Thu Sep 5 20:40:52 2013 +0300 drm/i915: Delay disabling of VGA memory until vgacon->fbcon handoff is done we delay the VGA memory disable until fbcon has initialized, and so there's a possibility that the power well got turned off during the fbcon modeset. Also vgacon_save_screen() will need the power well to be on to be able to read the VGA memory. So immediately after enabling the power well during init grab a refence for VGA purposes, and after all the VGA handling is done, release it. v2: Add intel_display_power_put() for the num_pipes==0 case Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> [danvet: Fix up the patch wiggle screw-up that I've done and which Paulo catched. Also polish spelling in the patch headline.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>		2013-10-01 07:45:07 +02:00
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drm	drm/i915: Fix unclaimed register access due to delayed VGA memory disable	2013-10-01 07:45:07 +02:00
host1x	Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux	2013-09-05 10:17:26 -07:00
vga	vgaarb: Fix VGA decodes changes	2013-09-03 19:17:59 +02:00
Makefile	gpu: host1x: Add host1x driver	2013-04-22 12:32:40 +02:00