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Commit 36c0cc61 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/i915: clean up media reset on gm45 



Originally I've thought that this fixes up the reset issues on my
gm45, but that was just a red herring due to b0rked testing.

Still I much prefer writing the right values (all other fields are
reserved) instead of potentially dragging gunk around. Hence also
clear the register to 0 after a reset.

Note that Cspec is a bit confused and doesn't explicitly say that all
the other bits in this register are "reserved, mbz" like usually.
Instead they're marked as "r/o, default value = 0" which semantically
amounts to the same thing.

v2: Stop claiming this fixes anything and return 0 if successful
instead of stack garbage.

v3: Pimp the commit message to explain exactly why I think the docs
allow us to ditch the rmw cycle, spurred by a discussion with Chris.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent eaba1b8f

drivers/gpu/drm/i915/i915_drv.c

+9 −8
Original line number Diff line number Diff line
@@ -798,28 +798,29 @@ static int i965_reset_complete(struct drm_device *dev) 
static int i965_do_reset(struct drm_device *dev)

{

	int ret;

	u8 gdrst;



	/*

	 * Set the domains we want to reset (GRDOM/bits 2 and 3) as

	 * well as the reset bit (GR/bit 0).  Setting the GR bit

	 * triggers the reset; when done, the hardware will clear it.

	 */

	pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);

	pci_write_config_byte(dev->pdev, I965_GDRST,

			      gdrst | GRDOM_RENDER |

			      GRDOM_RESET_ENABLE);

			      GRDOM_RENDER | GRDOM_RESET_ENABLE);

	ret =  wait_for(i965_reset_complete(dev), 500);

	if (ret)

		return ret;



	/* We can't reset render&media without also resetting display ... */

	pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);

	pci_write_config_byte(dev->pdev, I965_GDRST,

			      gdrst | GRDOM_MEDIA |

			      GRDOM_RESET_ENABLE);

			      GRDOM_MEDIA | GRDOM_RESET_ENABLE);



	return wait_for(i965_reset_complete(dev), 500);

	ret =  wait_for(i965_reset_complete(dev), 500);

	if (ret)

		return ret;



	pci_write_config_byte(dev->pdev, I965_GDRST, 0);



	return 0;

}



static int ironlake_do_reset(struct drm_device *dev)