[Intel-gfx] [PATCH] drm/i915: optionally ban context on first hang

[Chris Wilson]

On Tue, Sep 10, 2013 at 04:16:50PM +0300, Mika Kuoppala wrote:
> Current policy is to ban context if it manages to hang
> gpu in a certain time windows. Paul Berry asked if more
> strict policy could be available for use cases where
> the application doesn't know if the rendering command stream
> sent to gpu is valid or not.
> 
> Provide an option, flag on context creation time, to let
> userspace to set more strict policy for handling gpu hangs for
> this context. If context with this flag set ever hangs the gpu,
> it will be permanently banned from accessing the GPU.
> All subsequent batch submissions will return -EIO.
> 
> Requested-by: Paul Berry <stereotype441 at gmail.com>
> Cc: Paul Berry <stereotype441 at gmail.com>
> Cc: Ben Widawsky <ben at bwidawsk.net>
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_dma.c         |    3 +++
>  drivers/gpu/drm/i915/i915_drv.h         |    3 +++
>  drivers/gpu/drm/i915/i915_gem.c         |    9 ++++++++-
>  drivers/gpu/drm/i915/i915_gem_context.c |   12 +++++++++---
>  include/uapi/drm/i915_drm.h             |    5 +++++
>  5 files changed, 28 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 3de6050..4353458 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1003,6 +1003,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
>  	case I915_PARAM_HAS_EXEC_HANDLE_LUT:
>  		value = 1;
>  		break;
> +	case I915_PARAM_HAS_CONTEXT_BAN:
> +		value = 1;
> +		break;

As we add the flags, we have a better method for detecting whether the
context accepts the flags (just request that a first-ban context be
created and mark the failure as unsupported), and so the getparam is
redundant.

>  struct drm_i915_gem_context_create {
>  	/*  output: id of new context*/
>  	__u32 ctx_id;
>  	__u32 pad;
> +	__u64 flags;
>  };

I thought that the size of the ioctl was part of the ABI, but it does
look like extending it as you have done here is valid. TIL.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre