linux/drivers/gpu
Paulo Zanoni 9d9740f099 drm/i915: add some barriers when changing DIPs
On IVB and older, we basically have two registers: the control and the
data register. We write a few consecutitve times to the control
register, and we need these writes to arrive exactly in the specified
order.

Also, when we're changing the data register, we need to guarantee that
anything written to the control register already arrived (since
changing the control register can change where the data register
points to). Also, we need to make sure all the writes to the data
register happen exactly in the specified order, and we also *can't*
read the data register during this process, since reading and/or
writing it will change the place it points to.

So invoke the "better safe than sorry" rule and just be careful and
put barriers everywhere :)

On HSW we still have a control register that we write many times, but
we have many data registers.

Demanded-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-05-30 23:05:08 +02:00
..
drm drm/i915: add some barriers when changing DIPs 2012-05-30 23:05:08 +02:00
stub i915: select VIDEO_OUTPUT_CONTROL for ACPI_VIDEO 2011-04-13 09:10:25 +10:00
vga vga_switcheroo: Add the support for audio clients 2012-05-13 11:27:21 +02:00
Makefile gpu: Add Intel GMA500(Poulsbo) Stub Driver 2010-10-26 11:00:13 +10:00