Chris Wilson 0db8c96120 drm/i915: Re-enable GTT following a device reset ... Ville Syrjälä spotted that PGETBL_CTL was losing its enable bit upon a reset. That was causing the display to show garbage on his 945gm. On my i915gm the effect was far more severe; re-enabling the display following the reset without PGETBL_CTL being enabled lead to an immediate hard hang. We do have a routine to re-enable PGETBL_CTL which is applicable to gen2-4, although on gen4 it is documented that a graphics reset doesn't alter the register (no such wording is given for gen3) and should be safe to call to punch back in the enable bit. However, that leaves the question of whether we need to completely re-initialise the register and the rest of the GSM. For g33/pnv/gen4+, where we do have a configurable page table, its contents do seem to be kept, and so we should be able to recover without having to reinitialise the GTT from scratch (as prior to g33, that register is configured by the BIOS and we leave alone except for the enable bit). This appears to have been broken by commit 5fbd0418ee ("drm/i915: Re-enable GGTT earlier during resume on pre-gen6 platforms"), which moved the intel_enable_gtt() from i915_gem_init_hw() (also used by reset) to add it earlier during hw init and resume, missing the reset path. v2: Find the culprit, rearrange ggtt_enable to be before gem_init_hw to match init/resume Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Fixes: 5fbd0418ee ("drm/i915: Re-enable GGTT earlier during resume on pre-gen6 platforms") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101852 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Daniel Vetter <daniel@ffwll.ch> Reviewed-by: Daniel Vetter <daniel@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20170906111405.27110-1-chris@chris-wilson.co.uk Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>		2017-09-06 14:17:32 +01:00
..
drm	drm/i915: Re-enable GTT following a device reset	2017-09-06 14:17:32 +01:00
host1x	drm/tegra: Changes for v4.14-rc1	2017-08-21 17:37:33 +10:00
ipu-v3	drm: Convert to using %pOF instead of full_name	2017-07-26 13:45:06 +02:00
vga	sched/wait: Rename wait_queue_t => wait_queue_entry_t	2017-06-20 12:18:27 +02:00
Makefile