Hi Mauro and Chris,

On Mon, Jul 04, 2022 at 09:09:29AM +0100, Mauro Carvalho Chehab wrote:

From: Chris Wilson chris.p.wilson@intel.com

Avoid trying to invalidate the TLB in the middle of performing an engine reset, as this may result in the reset timing out. Currently, the TLB invalidate is only serialised by its own mutex, forgoing the uncore lock, but we can take the uncore->lock as well to serialise the mmio access, thereby serialising with the GDRST.

Tested on a NUC5i7RYB, BIOS RYBDWi35.86A.0380.2019.0517.1530 with i915 selftest/hangcheck.

Cc: stable@vger.kernel.org # Up to 4.4 Fixes: 7938d61591d3 ("drm/i915: Flush TLBs before releasing backing store") Reported-by: Mauro Carvalho Chehab mchehab@kernel.org Tested-by: Mauro Carvalho Chehab mchehab@kernel.org Reviewed-by: Mauro Carvalho Chehab mchehab@kernel.org Cc: Chris Wilson chris.p.wilson@intel.com Cc: Tvrtko Ursulin tvrtko.ursulin@linux.intel.com Cc: Thomas Hellström thomas.hellstrom@linux.intel.com Cc: Andi Shyti andi.shyti@intel.com Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org

---

To avoid mailbombing on a large number of people, only mailing lists were C/C on the cover. See [PATCH v3 0/2] at: https://lore.kernel.org/all/cover.1656921701.git.mchehab@kernel.org/

drivers/gpu/drm/i915/gt/intel_gt.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c index 8da3314bb6bf..68c2b0d8f187 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt.c +++ b/drivers/gpu/drm/i915/gt/intel_gt.c @@ -952,6 +952,20 @@ void intel_gt_invalidate_tlbs(struct intel_gt *gt) mutex_lock(&gt->tlb_invalidate_lock); intel_uncore_forcewake_get(uncore, FORCEWAKE_ALL);

• spin_lock_irq(&uncore->lock); /* serialise invalidate with GT reset */
• for_each_engine(engine, gt, id) {

• struct reg_and_bit rb;
  

• rb = get_reg_and_bit(engine, regs == gen8_regs, regs, num);
  

• if (!i915_mmio_reg_offset(rb.reg))
  

• 	continue;
  

• intel_uncore_write_fw(uncore, rb.reg, rb.bit);
  

• }
• spin_unlock_irq(&uncore->lock);

looks good,

Reviewed-by: Andi Shyti andi.shyti@linux.intel.com

Thanks, Andi

for_each_engine(engine, gt, id) { /* * HW architecture suggest typical invalidation time at 40us, @@ -966,7 +980,6 @@ void intel_gt_invalidate_tlbs(struct intel_gt *gt) if (!i915_mmio_reg_offset(rb.reg)) continue;

• intel_uncore_write_fw(uncore, rb.reg, rb.bit);
  

  if (__intel_wait_for_register_fw(uncore, rb.reg, rb.bit, 0, timeout_us, timeout_ms,

-- 2.36.1