[Intel-gfx] [PATCH 1/3] drm/i915: Verify address field of PCBR register.

[Daniel Vetter]

On Sun, Dec 08, 2013 at 01:52:35PM +0530, deepak.s at intel.com wrote:
> From: Deepak S <deepak.s at intel.com>
> 
> On VLV the PCBR register has other bits besides the pcbr address
> field. Verify only address field setup by BIOS to make sure we don't
> misinterpret the PCBR setup.
> 
> Signed-off-by: Deepak S <deepak.s at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index e6d98fe..2e1340f 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4036,7 +4036,12 @@ static void valleyview_setup_pctx(struct drm_device *dev)
>  	int pctx_size = 24*1024;
>  
>  	pcbr = I915_READ(VLV_PCBR);
> -	if (pcbr) {
> +
> +	/* PCBR Format: Bits 31:12 - Base address of Process Context
> +	 * 		Bits 11:1 - Reserved
> +	 * 		Bit 0 - PCBR Lock
> +	 * Check only address field if already setup by BIOS */
> +	if (pcbr >> 12) {

I'd just add a VLV_PCBR_ADDR_MASK #define and & it. That's a bit more the
idiom we usually use, and also allows us to ditcht the comment. You could
even add a VLV_PCBR_LOCK #define if you want.
-Daniel

>  		/* BIOS set it up already, grab the pre-alloc'd space */
>  		int pcbr_offset;
>  
> -- 
> 1.8.4.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch