[Jaunty SRU] LP#349992 Allow to disable GEM on i915 chipset

[Tim Gardner]

Ike Panhc wrote:
>> Description
> SRU justification:
> 
> Impact: Allow to disable GEM on i915 chipset
> 
> Fix: Allow to disable GEM on i915 chipset with module parameter
> 
> Note:
> We could have a proper fix by commit 280b713b5b0fd84cf2469098aee88acbb5de859c
> from upstream, but it is a huge commit, the simple one is to allow driver to
> disable gem when loaded.
> 
> 
>> Request-pull
> The following changes since commit 905e2094d74d7afa9f8ca9afcca20ceb67af6ad1:
>   Tim Gardner (1):
>         UBUNTU: [Config] Updated comments on debug package generation.
> 
> are available in the git repository at:
> 
>   git://kernel.ubuntu.com/ikepanhc/ike-jaunty.git lp#349992
> 
> Ike Panhc (1):
>       UBUNTU: SAUCE: Allow to disable GEM on i915
> 
>  drivers/gpu/drm/i915/i915_dma.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> 
>> Patch
> From 07d4e3316ca5d8f050959189e6f1ebc76f472eea Mon Sep 17 00:00:00 2001
> From: Ike Panhc <ike.pan at canonical.com>
> Date: Wed, 6 May 2009 20:51:45 +0800
> Subject: [PATCH] UBUNTU: SAUCE: Allow to disable GEM on i915
> 
> OriginalAuthor: Vasily Khoruzhick <anarsoul at gmail.com>
> OriginalLocation: http://bugs.freedesktop.org/show_bug.cgi?id=16835
> Bug: #349992
> BugLink: https://bugs.launchpad.net/ubuntu/+bug/349992
> 
> Allow to disable GEM on i915 drivers for improvement 3D performance.
> 
> Please drop this patch if the following commit is pulled from upstream.
>   commit 280b713b5b0fd84cf2469098aee88acbb5de859c
>   Author: Eric Anholt <eric at anholt.net>
>   drm/i915: Allow tiling of objects with bit 17 swizzling by the CPU.
> 
> Signed-off-by: Ike Panhc <ike.pan at canonical.com>
> ---
>  drivers/gpu/drm/i915/i915_dma.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index c6d5528..020969d 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -31,6 +31,9 @@
>  #include "i915_drm.h"
>  #include "i915_drv.h"
>  
> +static int gem_enable = 1;
> +module_param(gem_enable, int, 0400);
> +
>  /* Really want an OS-independent resettable timer.  Would like to have
>   * this loop run for (eg) 3 sec, but have the timer reset every time
>   * the head pointer changes, so that EBUSY only happens if the ring
> @@ -835,7 +838,7 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
>  	dev_priv->has_gem = 0;
>  #else
>  	/* enable GEM by default */
> -	dev_priv->has_gem = 1;
> +	dev_priv->has_gem = gem_enable;
>  #endif
>  
>  	dev->driver->get_vblank_counter = i915_get_vblank_counter;

NACK - lets wait and see how Andy's proposed MCHBAR and MTRR aperture
patches affect performance. Please ask bug responders to test once
Stefan gets a new kernel uploaded.

rtg
-- 
Tim Gardner tim.gardner at canonical.com