[Precise][SRU][PATCH 1/1] drm/i915: Periodically sanity check power management

Seth Forshee seth.forshee at canonical.com
Thu Mar 7 20:46:08 UTC 2013

On Thu, Mar 07, 2013 at 12:14:55PM -0800, leann.ogasawara at canonical.com wrote:
> From: Chris Wilson <chris at chris-wilson.co.uk>
> BugLink: http://bugs.launchpad.net/bugs/1146425
> Every time we use the device after a period of idleness, check that the
> power management setup is still sane. This is to workaround a bug
> whereby it seems that we begin suppressing power management interrupts,
> preventing SandyBridge+ from going into turbo mode.
> This patch does have a side-effect. It removes the mark-busy for just
> moving the cursor - we don't want to increase the render clock just for
> the sprite, though we may want to bump the display frequency. I'd argue
> that we do not, and certainly don't want to take the struct_mutex here
> due to the large latencies that introduces.

Regarding this last paragraph: The upstream commit does remove a call to
intel_mark_busy() from intel_crtc_update_cursor(), which I suspect is
what this refers to. That call is present in our precise kernel but is
not removed by this patch. Do you know whether or not that omission was


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