On 11/02/2022 20:27, alyssa.rosenzweig@collabora.com wrote:
From: Alyssa Rosenzweig alyssa.rosenzweig@collabora.com
Some Valhall GPUs require resets when encountering bus faults due to occlusion query writes. Add the issue bit for this and handle it.
Signed-off-by: Alyssa Rosenzweig alyssa.rosenzweig@collabora.com
Reviewed-by: Steven Price steven.price@arm.com (although one nit below)
Just in case any one is wondering - these bus faults occur when switching the GPU's MMU to unmapped - it's not a normal "bus fault" from the external bus. This is triggered by an attempt to read unmapped memory which is completed by the driver by switching the entire MMU to unmapped.
drivers/gpu/drm/panfrost/panfrost_device.c | 9 +++++++-- drivers/gpu/drm/panfrost/panfrost_issues.h | 4 ++++ 2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c index 7f51a4682ccb..ee612303f076 100644 --- a/drivers/gpu/drm/panfrost/panfrost_device.c +++ b/drivers/gpu/drm/panfrost/panfrost_device.c @@ -11,6 +11,7 @@ #include "panfrost_device.h" #include "panfrost_devfreq.h" #include "panfrost_features.h" +#include "panfrost_issues.h" #include "panfrost_gpu.h" #include "panfrost_job.h" #include "panfrost_mmu.h" @@ -380,9 +381,13 @@ const char *panfrost_exception_name(u32 exception_code) bool panfrost_exception_needs_reset(const struct panfrost_device *pfdev, u32 exception_code) {
- /* Right now, none of the GPU we support need a reset, but this
* might change.
- /* If an occlusion query write causes a bus fault on affected GPUs,
* future fragment jobs may hang. Reset to workaround.- if (exception_code == DRM_PANFROST_EXCEPTION_JOB_BUS_FAULT)
return panfrost_has_hw_issue(pfdev, HW_ISSUE_TTRX_3076);- /* No other GPUs we support need a reset */ return false;
}
diff --git a/drivers/gpu/drm/panfrost/panfrost_issues.h b/drivers/gpu/drm/panfrost/panfrost_issues.h index a66692663833..058f6a4c8435 100644 --- a/drivers/gpu/drm/panfrost/panfrost_issues.h +++ b/drivers/gpu/drm/panfrost/panfrost_issues.h @@ -128,6 +128,10 @@ enum panfrost_hw_issue { /* Must set SC_VAR_ALGORITHM */ HW_ISSUE_TTRX_2968_TTRX_3162,
- /* Bus fault from occlusion query write may cause future fragment jobs
* to hang */
NIT: Kernel comment style has the "/*" and "*/" on lines by themselves for multi-line comments. checkpatch will complain!
- HW_ISSUE_TTRX_3076,
- HW_ISSUE_END
};