On Fri, Jul 24, 2026 at 03:33:07PM +0530, Mallesh Koujalagi wrote:
> Use fault-inject framework to trigger punit_error_handler()
> for testing.
>
> Usage:
> echo 100 > .../inject_punit_error/probability
> echo 1 > .../inject_punit_error/times
>
> Signed-off-by: Mallesh Koujalagi <[email protected]>
> ---
> drivers/gpu/drm/xe/xe_debugfs.c | 4 ++++
> drivers/gpu/drm/xe/xe_debugfs.h | 2 ++
> drivers/gpu/drm/xe/xe_ras.c | 17 +++++++++++++++++
> 3 files changed, 23 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
> index 5a3877fcb0f0..5599d493feca 100644
> --- a/drivers/gpu/drm/xe/xe_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_debugfs.c
> @@ -42,6 +42,7 @@
>
> DECLARE_FAULT_ATTR(gt_reset_failure);
> DECLARE_FAULT_ATTR(inject_csc_hw_error);
> +DECLARE_FAULT_ATTR(inject_punit_error);
>
> static bool csc_hw_error_available(struct xe_device *xe)
> {
> @@ -62,6 +63,8 @@ static struct {
> { .name = "inject_csc_hw_error",
> .attr = &inject_csc_hw_error,
> .is_visible = csc_hw_error_available },
> + { .name = "inject_punit_error",
> + .attr = &inject_punit_error },
> };
>
> /*
> @@ -76,6 +79,7 @@ bool xe_fault_##name(void) \
>
> FAULT_ACTION(gt_reset, gt_reset_failure)
> FAULT_ACTION(csc_hw_error, inject_csc_hw_error)
> +FAULT_ACTION(punit_error, inject_punit_error)
>
> static void xe_fault_inject_debugfs_register(struct xe_device *xe,
> struct dentry *root)
> diff --git a/drivers/gpu/drm/xe/xe_debugfs.h b/drivers/gpu/drm/xe/xe_debugfs.h
> index cd56f7442b99..dd57914dd4f2 100644
> --- a/drivers/gpu/drm/xe/xe_debugfs.h
> +++ b/drivers/gpu/drm/xe/xe_debugfs.h
> @@ -13,10 +13,12 @@ struct xe_device;
> #ifdef CONFIG_DEBUG_FS
> bool xe_fault_gt_reset(void);
> bool xe_fault_csc_hw_error(void);
> +bool xe_fault_punit_error(void);
> void xe_debugfs_register(struct xe_device *xe);
> #else
> static inline bool xe_fault_gt_reset(void) { return false; }
> static inline bool xe_fault_csc_hw_error(void) { return false; }
> +static inline bool xe_fault_punit_error(void) { return false; }
> static inline void xe_debugfs_register(struct xe_device *xe) { }
> #endif
>
> diff --git a/drivers/gpu/drm/xe/xe_ras.c b/drivers/gpu/drm/xe/xe_ras.c
> index 92b4181026cb..da06c16cf7ed 100644
> --- a/drivers/gpu/drm/xe/xe_ras.c
> +++ b/drivers/gpu/drm/xe/xe_ras.c
> @@ -3,6 +3,7 @@
> * Copyright © 2026 Intel Corporation
> */
>
> +#include "xe_debugfs.h"
> #include "xe_device.h"
> #include "xe_drm_ras.h"
> #include "xe_pm.h"
> @@ -391,6 +392,22 @@ enum xe_ras_recovery_action xe_ras_process_errors(struct
> xe_device *xe)
> size_t rlen;
> int ret;
>
> + /*
> + * Only allow the injected PUNIT error once the DRM device is
> registered.
That entirely defeats the purpose! :)
Sashiko identified this corner case so I asked you to ensure that this is
covered
and to prove that you should provide a fault-inject with test case.
But then you are skipping exactly the corner case. That makes absolutely no
sense.
> + * xe_ras_process_errors() also runs during probe (via xe_ras_init()),
> before
> + * drm_dev_register() calls device_add() on the DRM minor's kdev. At
> that
> + * point kdev->kobj.parent is not yet linked into the sysfs hierarchy,
> so
> + * kobject_get_path() returns "/card0" instead of the real sysfs path.
> + * drm_dev_wedged_event() would then emit a KOBJ_CHANGE uevent with a
> wrong
> + * DEVPATH that udev cannot resolve, silently dropping the event and
> leaving
> + * the cold-reset recovery broken.
> + */
> + if (xe->drm.registered && xe_fault_punit_error()) {
> + xe_err(xe, "[RAS]: PUNIT error injected\n");
> + punit_error_handler(xe);
> + return XE_RAS_RECOVERY_ACTION_DISCONNECT;
> + }
> +
> if (!xe->info.has_sysctrl)
> return XE_RAS_RECOVERY_ACTION_RESET;
>
> --
> 2.48.1
>
