On 5/19/2024 1:38 AM, Dmitry Baryshkov wrote:
On Fri, May 17, 2024 at 04:37:56PM -0700, Abhinav Kumar wrote:
In preparation to register a iommu fault handler for display
related modules, register a fault handler for the backing
mmu object of msm_kms.
Currently, the fault handler only captures the display snapshot
but we can expand this later if more information needs to be
added to debug display mmu faults.
Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/msm_kms.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/gpu/drm/msm/msm_kms.c b/drivers/gpu/drm/msm/msm_kms.c
index af6a6fcb1173..62c8e6163e81 100644
--- a/drivers/gpu/drm/msm/msm_kms.c
+++ b/drivers/gpu/drm/msm/msm_kms.c
@@ -200,6 +200,28 @@ struct msm_gem_address_space *msm_kms_init_aspace(struct drm_device *dev)
return aspace;
}
+static int msm_kms_fault_handler(void *arg, unsigned long iova, int flags, void *data)
+{
+ struct msm_kms *kms = arg;
+ struct msm_disp_state *state;
+ int ret;
+
+ ret = mutex_lock_interruptible(&kms->dump_mutex);
+ if (ret)
+ return ret;
+
+ state = msm_disp_snapshot_state_sync(kms);
+
+ mutex_unlock(&kms->dump_mutex);
+
+ if (IS_ERR(state)) {
+ DRM_DEV_ERROR(kms->dev->dev, "failed to capture snapshot\n");
+ return PTR_ERR(state);
+ }
+
+ return 0;
Hmm, after reading the rest of the code, this means that we won't get
the error on the console. Could you please change this to -ENOSYS?
I am perhaps missing something here. Are you referring to this
documentation?
* Specifically, -ENOSYS is returned if a fault handler isn't installed
* (though fault handlers can also return -ENOSYS, in case they want to
* elicit the default behavior of the IOMMU drivers).
*/
int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
unsigned long iova, int flags)
Doesnt this mean ENOSYS is when fault handler is not installed?
Because the console print will come if we return 0?
if (!report_iommu_fault(ctx->domain, ctx->dev, iova, 0)) {
dev_err_ratelimited(ctx->dev,
"Unhandled context fault: fsr=0x%x, "
"iova=0x%016llx, fsynr=0x%x, cb=%d\n",
fsr, iova, fsynr, ctx->asid);
}
+}
+
void msm_drm_kms_uninit(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
@@ -261,6 +283,9 @@ int msm_drm_kms_init(struct device *dev, const struct drm_driver *drv)
goto err_msm_uninit;
}
+ if (kms->aspace)
+ msm_mmu_set_fault_handler(kms->aspace->mmu, kms, msm_kms_fault_handler);
+
drm_helper_move_panel_connectors_to_head(ddev);
drm_for_each_crtc(crtc, ddev) {
--
2.44.0
