Re: [PATCH] drm/i915: Make i915 events part of uapi

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Jul 16, 2013 at 04:41:13PM -0700, Ben Widawsky wrote:
> Make the uevent strings part of the user API for people who wish to
> write their own listeners.
> 
> CC: Chad Versace <chad.versace@linux.intel.com>
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net>

One thing I've toyed around with a bit is that we should add kerneldoc to
our uapi headers and create a DocBook out of it (maybe as a subsection in
the drm userspace api chapter). I guess the DocBook integration needs an
overall approach, but we should start to add comments to each piece of
userspace api to clearly spec them. See below for what I have in mind ...
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 8 ++++----
>  include/uapi/drm/i915_drm.h     | 3 +++
>  2 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 9910699..60fa513 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -812,7 +812,7 @@ static void ivybridge_parity_work(struct work_struct *work)
>  
>  	mutex_unlock(&dev_priv->dev->struct_mutex);
>  
> -	parity_event[0] = "L3_PARITY_ERROR=1";
> +	parity_event[0] = I915_L3_PARITY_EVENT"=1";
>  	parity_event[1] = kasprintf(GFP_KERNEL, "ROW=%d", row);
>  	parity_event[2] = kasprintf(GFP_KERNEL, "BANK=%d", bank);
>  	parity_event[3] = kasprintf(GFP_KERNEL, "SUBBANK=%d", subbank);
> @@ -1435,9 +1435,9 @@ static void i915_error_work_func(struct work_struct *work)
>  						    gpu_error);
>  	struct drm_device *dev = dev_priv->dev;
>  	struct intel_ring_buffer *ring;
> -	char *error_event[] = { "ERROR=1", NULL };
> -	char *reset_event[] = { "RESET=1", NULL };
> -	char *reset_done_event[] = { "ERROR=0", NULL };
> +	char *error_event[] = { I915_ERROR_EVENT"=1", NULL };
> +	char *reset_event[] = { I915_RESET_EVENT"=1", NULL };
> +	char *reset_done_event[] = { I915_ERROR_EVENT"=0", NULL };
>  	int i, ret;
>  
>  	kobject_uevent_env(&dev->primary->kdev.kobj, KOBJ_CHANGE, error_event);
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 923ed7f..25a3e74 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -33,6 +33,9 @@
>   * subject to backwards-compatibility constraints.
>   */
>  

/**
 * DOC uevents generated by i915 on it's device node
 *
 * These are events generated in addition to the standardized uevents
 * genereated by the drm core (like signalling connector state changes).
 */

/**
 * I915_L3_PARITY_EVENT - l3 parity event
 *
 * Generated when the driver receives a parity mismatch event from the gpu
 * l3 cache. Additional information supplied is ROW, BANK, SUBBANK of the
 * affected cacheline. Userspace should keep track of these events and if
 * a specific cache-line seems to have a persistent error remap it with
 * the l3 remapping tool supplied in intel-gpu-tools
 *
 * The value supplied with the event is always 1.
 */
> +#define I915_L3_PARITY_EVENT "L3_PARITY_ERROR"
> +#define I915_ERROR_EVENT "ERROR"
> +#define I915_RESET_EVENT "RESET"

I'll let you cook up something nice for the other two ;-)

Cheers, Daniel
>  
>  /* Each region is a minimum of 16k, and there are at most 255 of them.
>   */
> -- 
> 1.8.3.3
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch