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From: Eric Anholt <eric@anholt.net>
To: intel-gfx@lists.freedesktop.org
Cc: Ben Widawsky <ben@bwidawsk.net>
Subject: Re: [PATCH v2] drm/i915: add register read IOCTL
Date: Wed, 18 Jul 2012 10:14:46 -0700	[thread overview]
Message-ID: <87pq7txa7t.fsf@eliezer.anholt.net> (raw)
In-Reply-To: <1342116066-12164-1-git-send-email-ben@bwidawsk.net>


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Ben Widawsky <ben@bwidawsk.net> writes:

> The interface's immediate purpose is to do synchronous timestamp queries
> as required by GL_TIMESTAMP. The GPU has a register for reading the
> timestamp but because that would normally require root access through
> libpciaccess, the IOCTL can provide this service instead.
>
> Currently the implementation whitelists only the render ring timestamp
> register, because that is the only thing we need to expose at this time.
>
> v2: make size implicit based on the register offset
> Add a generation check

> diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
> index 8cc7083..fbe7757 100644
> --- a/include/drm/i915_drm.h
> +++ b/include/drm/i915_drm.h
> @@ -203,6 +203,7 @@ typedef struct _drm_i915_sarea {
>  #define DRM_I915_GEM_WAIT	0x2c
>  #define DRM_I915_GEM_CONTEXT_CREATE	0x2d
>  #define DRM_I915_GEM_CONTEXT_DESTROY	0x2e
> +#define DRM_I915_REG_READ	0x30

Is 0x2f some other outstanding ioctl?

Other than that,

Reviewed-by: Eric Anholt <eric@anholt.net>

Note: we have requests both by Arjan and by Valve for the functionality
that this patch will allow.

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  parent reply	other threads:[~2012-07-18 17:14 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-12  0:07 [PATCH] drm/i915: add register read IOCTL Ben Widawsky
2012-07-12  0:08 ` [PATCH] reg_read: basic register read ioctl test Ben Widawsky
2012-07-12  8:06   ` Daniel Vetter
2012-07-12  7:58 ` [PATCH] drm/i915: add register read IOCTL Daniel Vetter
2012-07-12  8:11   ` Chris Wilson
2012-07-12 18:01 ` [PATCH v2] " Ben Widawsky
2012-07-12 18:01   ` [PATCH] reg_read: basic register read ioctl test Ben Widawsky
2012-07-18 17:14   ` Eric Anholt [this message]
2012-07-18 17:22     ` [PATCH v2] drm/i915: add register read IOCTL Ben Widawsky
2012-07-18 18:12       ` Daniel Vetter
2012-07-12 19:42 ` [PATCH] " Eric Anholt
2012-07-12 20:08   ` Ben Widawsky

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