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?
> +}
> +
> 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
>
--
With best wishes
Dmitry
