Re: [PATCH v2 2/5] drm: Add DRM_WEDGE_RECOVERY_COLD_RESET for power management unit error

Tauro, Riana
2026-03-30T05:26:34Z

On 3/18/2026 12:10 PM, Mallesh Koujalagi wrote:
> Introduce DRM_WEDGE_RECOVERY_COLD_RESET (BIT(4)) recovery method to
> handle power management unit errors requiring complete device power
> cycling.

Same as other comments, do not use power management unit errors.

Keep the documentation in drm-layer vendor agnostic so that anyone can
use this method for

any scenario that requires cold-reset

Thanks
Riana

>
> This method addresses scenarios where recovery mechanisms
> (driver reload, PCIe reset, etc.) are insufficient to restore
> device functionality. When set, it indicates to userspace that
> only a full cold reset can recover the device from its current error
> state. The cold reset method serves as a last resort for power management
> unit errors.
>
> Signed-off-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
> ---
> drivers/gpu/drm/drm_drv.c | 2 ++
> include/drm/drm_device.h | 1 +
> 2 files changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 6b965c3d3307..2dace9070531 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -535,6 +535,8 @@ static const char *drm_get_wedge_recovery(unsigned int opt)
> return "bus-reset";
> case DRM_WEDGE_RECOVERY_VENDOR:
> return "vendor-specific";
> + case DRM_WEDGE_RECOVERY_COLD_RESET:
> + return "cold-reset";
> default:
> return NULL;
> }
> diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
> index bc78fb77cc27..3e386eb42023 100644
> --- a/include/drm/drm_device.h
> +++ b/include/drm/drm_device.h
> @@ -37,6 +37,7 @@ struct pci_controller;
> #define DRM_WEDGE_RECOVERY_REBIND BIT(1) /* unbind + bind driver */
> #define DRM_WEDGE_RECOVERY_BUS_RESET BIT(2) /* unbind + reset bus device + bind */
> #define DRM_WEDGE_RECOVERY_VENDOR BIT(3) /* vendor specific recovery method */
> +#define DRM_WEDGE_RECOVERY_COLD_RESET BIT(4) /* full device cold reset */
>
> /**
> * struct drm_wedge_task_info - information about the guilty task of a wedge dev