diff options
Diffstat (limited to 'drivers/gpu/drm/i915/gt/intel_reset.c')
| -rw-r--r-- | drivers/gpu/drm/i915/gt/intel_reset.c | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c index 8cea42379dd7..48aed34e19df 100644 --- a/drivers/gpu/drm/i915/gt/intel_reset.c +++ b/drivers/gpu/drm/i915/gt/intel_reset.c @@ -257,6 +257,7 @@ out: static int gen6_hw_domain_reset(struct intel_gt *gt, u32 hw_domain_mask) { struct intel_uncore *uncore = gt->uncore; + int loops = 2; int err; /* @@ -264,17 +265,38 @@ static int gen6_hw_domain_reset(struct intel_gt *gt, u32 hw_domain_mask) * for fifo space for the write or forcewake the chip for * the read */ - intel_uncore_write_fw(uncore, GEN6_GDRST, hw_domain_mask); + do { + intel_uncore_write_fw(uncore, GEN6_GDRST, hw_domain_mask); - /* Wait for the device to ack the reset requests */ - err = __intel_wait_for_register_fw(uncore, - GEN6_GDRST, hw_domain_mask, 0, - 500, 0, - NULL); + /* + * Wait for the device to ack the reset requests. + * + * On some platforms, e.g. Jasperlake, we see that the + * engine register state is not cleared until shortly after + * GDRST reports completion, causing a failure as we try + * to immediately resume while the internal state is still + * in flux. If we immediately repeat the reset, the second + * reset appears to serialise with the first, and since + * it is a no-op, the registers should retain their reset + * value. However, there is still a concern that upon + * leaving the second reset, the internal engine state + * is still in flux and not ready for resuming. + */ + err = __intel_wait_for_register_fw(uncore, GEN6_GDRST, + hw_domain_mask, 0, + 2000, 0, + NULL); + } while (err == 0 && --loops); if (err) DRM_DEBUG_DRIVER("Wait for 0x%08x engines reset failed\n", hw_domain_mask); + /* + * As we have observed that the engine state is still volatile + * after GDRST is acked, impose a small delay to let everything settle. + */ + udelay(50); + return err; } |