[oneiric] drm/i915: set GFX_MODE to pre-Ivybridge default value even on Ivybridge

From: Jesse Barnes <jbarnes@virtuousgeek.org>

Prior to Ivybridge, the GFX_MODE would default to 0x800, meaning that
MI_FLUSH would flush the TLBs in addition to the rest of the caches
indicated in the MI_FLUSH command.  However starting with Ivybridge, the
register defaults to 0x2800 out of reset, meaning that to invalidate the
TLB we need to use PIPE_CONTROL.  Since we're not doing that yet, go
back to the old default so things work.

v2: don't forget to actually *clear* the new bit

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
(cherry picked from commit b095cd0a0ccdbc00c9fd99d90b22f8563687971f)

Signed-off-by: Robert Hooker <robert.hooker@canonical.com>
---
 drivers/gpu/drm/i915/i915_reg.h         |    4 ++++
 drivers/gpu/drm/i915/intel_ringbuffer.c |    4 ++++
 2 files changed, 8 insertions(+), 0 deletions(-)

This is a commit in 3.1 that fixes a frequent GPU hang on ivybridge
and is not yet in stable.
It adds a few new register defines, then uses them only on GEN7 which
is ivybridge so it does
not affect any other generation making it safe to apply. It is a clean
cherry-pick into oneiric and
was tested on an ivybridge machine.

On 09/06/2011 08:36 AM, Robert Hooker wrote:
> From: Jesse Barnes<jbarnes@virtuousgeek.org>
>
> Prior to Ivybridge, the GFX_MODE would default to 0x800, meaning that
> MI_FLUSH would flush the TLBs in addition to the rest of the caches
> indicated in the MI_FLUSH command.  However starting with Ivybridge, the
> register defaults to 0x2800 out of reset, meaning that to invalidate the
> TLB we need to use PIPE_CONTROL.  Since we're not doing that yet, go
> back to the old default so things work.
>
> v2: don't forget to actually *clear* the new bit
>
> Reviewed-by: Eric Anholt<eric@anholt.net>
> Reviewed-by: Chris Wilson<chris@chris-wilson.co.uk>
> Tested-by: Kenneth Graunke<kenneth@whitecape.org>
> Signed-off-by: Jesse Barnes<jbarnes@virtuousgeek.org>
> (cherry picked from commit b095cd0a0ccdbc00c9fd99d90b22f8563687971f)
>
> Signed-off-by: Robert Hooker<robert.hooker@canonical.com>
> ---
>   drivers/gpu/drm/i915/i915_reg.h         |    4 ++++
>   drivers/gpu/drm/i915/intel_ringbuffer.c |    4 ++++
>   2 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 5d5def7..2c34d07 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -367,6 +367,7 @@
>   # define MI_FLUSH_ENABLE				(1<<  11)
>
>   #define GFX_MODE	0x02520
> +#define GFX_MODE_GEN7	0x0229c
>   #define   GFX_RUN_LIST_ENABLE		(1<<15)
>   #define   GFX_TLB_INVALIDATE_ALWAYS	(1<<13)
>   #define   GFX_SURFACE_FAULT_ENABLE	(1<<12)
> @@ -374,6 +375,9 @@
>   #define   GFX_PSMI_GRANULARITY		(1<<10)
>   #define   GFX_PPGTT_ENABLE		(1<<9)
>
> +#define GFX_MODE_ENABLE(bit) (((bit)<<  16) | (bit))
> +#define GFX_MODE_DISABLE(bit) (((bit)<<  16) | (0))
> +
>   #define SCPD0		0x0209c /* 915+ only */
>   #define IER		0x020a0
>   #define IIR		0x020a4
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 1f61fc7..996264e 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -289,6 +289,10 @@ static int init_render_ring(struct intel_ring_buffer *ring)
>   		if (IS_GEN6(dev) || IS_GEN7(dev))
>   			mode |= MI_FLUSH_ENABLE<<  16 | MI_FLUSH_ENABLE;
>   		I915_WRITE(MI_MODE, mode);
> +		if (IS_GEN7(dev))
> +			I915_WRITE(GFX_MODE_GEN7,
> +				   GFX_MODE_DISABLE(GFX_TLB_INVALIDATE_ALWAYS) |
> +				   GFX_MODE_ENABLE(GFX_REPLAY_MODE));
>   	}
>
>   	if (INTEL_INFO(dev)->gen>= 6) {