diff options
Diffstat (limited to 'debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch')
| -rw-r--r-- | debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch | 99 |
1 files changed, 0 insertions, 99 deletions
diff --git a/debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch b/debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch deleted file mode 100644 index 5869667030..0000000000 --- a/debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch +++ /dev/null @@ -1,99 +0,0 @@ -From: Tvrtko Ursulin <tvrtko.ursulin@intel.com> -Date: Wed, 5 Jul 2023 10:30:25 +0100 -Subject: [PATCH] drm/i915: Do not disable preemption for resets -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz - -Commit ade8a0f59844 ("drm/i915: Make all GPU resets atomic") added a -preempt disable section over the hardware reset callback to prepare the -driver for being able to reset from atomic contexts. - -In retrospect I can see that the work item at a time was about removing -the struct mutex from the reset path. Code base also briefly entertained -the idea of doing the reset under stop_machine in order to serialize -userspace mmap and temporary glitch in the fence registers (see -eb8d0f5af4ec ("drm/i915: Remove GPU reset dependence on struct_mutex"), -but that never materialized and was soon removed in 2caffbf11762 -("drm/i915: Revoke mmaps and prevent access to fence registers across -reset") and replaced with a SRCU based solution. - -As such, as far as I can see, today we still have a requirement that -resets must not sleep (invoked from submission tasklets), but no need to -support invoking them from a truly atomic context. - -Given that the preemption section is problematic on RT kernels, since the -uncore lock becomes a sleeping lock and so is invalid in such section, -lets try and remove it. Potential downside is that our short waits on GPU -to complete the reset may get extended if CPU scheduling interferes, but -in practice that probably isn't a deal breaker. - -In terms of mechanics, since the preemption disabled block is being -removed we just need to replace a few of the wait_for_atomic macros into -busy looping versions which will work (and not complain) when called from -non-atomic sections. - -Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> -Cc: Chris Wilson <chris.p.wilson@intel.com> -Cc: Paul Gortmaker <paul.gortmaker@windriver.com> -Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Link: https://lore.kernel.org/r/20230705093025.3689748-1-tvrtko.ursulin@linux.intel.com -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> ---- - drivers/gpu/drm/i915/gt/intel_reset.c | 12 +++++------- - 1 file changed, 5 insertions(+), 7 deletions(-) - ---- a/drivers/gpu/drm/i915/gt/intel_reset.c -+++ b/drivers/gpu/drm/i915/gt/intel_reset.c -@@ -164,13 +164,13 @@ static int i915_do_reset(struct intel_gt - /* Assert reset for at least 20 usec, and wait for acknowledgement. */ - pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE); - udelay(50); -- err = wait_for_atomic(i915_in_reset(pdev), 50); -+ err = _wait_for_atomic(i915_in_reset(pdev), 50, 0); - - /* Clear the reset request. */ - pci_write_config_byte(pdev, I915_GDRST, 0); - udelay(50); - if (!err) -- err = wait_for_atomic(!i915_in_reset(pdev), 50); -+ err = _wait_for_atomic(!i915_in_reset(pdev), 50, 0); - - return err; - } -@@ -190,7 +190,7 @@ static int g33_do_reset(struct intel_gt - struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev); - - pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE); -- return wait_for_atomic(g4x_reset_complete(pdev), 50); -+ return _wait_for_atomic(g4x_reset_complete(pdev), 50, 0); - } - - static int g4x_do_reset(struct intel_gt *gt, -@@ -207,7 +207,7 @@ static int g4x_do_reset(struct intel_gt - - pci_write_config_byte(pdev, I915_GDRST, - GRDOM_MEDIA | GRDOM_RESET_ENABLE); -- ret = wait_for_atomic(g4x_reset_complete(pdev), 50); -+ ret = _wait_for_atomic(g4x_reset_complete(pdev), 50, 0); - if (ret) { - GT_TRACE(gt, "Wait for media reset failed\n"); - goto out; -@@ -215,7 +215,7 @@ static int g4x_do_reset(struct intel_gt - - pci_write_config_byte(pdev, I915_GDRST, - GRDOM_RENDER | GRDOM_RESET_ENABLE); -- ret = wait_for_atomic(g4x_reset_complete(pdev), 50); -+ ret = _wait_for_atomic(g4x_reset_complete(pdev), 50, 0); - if (ret) { - GT_TRACE(gt, "Wait for render reset failed\n"); - goto out; -@@ -785,9 +785,7 @@ int __intel_gt_reset(struct intel_gt *gt - reset_mask = wa_14015076503_start(gt, engine_mask, !retry); - - GT_TRACE(gt, "engine_mask=%x\n", reset_mask); -- preempt_disable(); - ret = reset(gt, reset_mask, retry); -- preempt_enable(); - - wa_14015076503_end(gt, reset_mask); - } |