[Intel-gfx] [PATCH 3/3] drm/i915: Implement 16GB dimm wa for latency level-0

[Ville Syrjälä]

On Sat, Jul 14, 2018 at 07:40:43PM +0530, Kumar, Mahesh wrote:
> Hi,
> 
> Thanks for review.
> 
> 
> On 7/13/2018 8:27 PM, Ville Syrjälä wrote:
> > On Fri, Jul 13, 2018 at 07:41:24PM +0530, Mahesh Kumar wrote:
> >> Memory with 16GB dimms require an increase of 1us in level-0 latency.
> >> This patch implements the same.
> >> Bspec: 4381
> >>
> >> Signed-off-by: Mahesh Kumar <mahesh1.kumar at intel.com>
> >> ---
> >>   drivers/gpu/drm/i915/i915_drv.c | 35 +++++++++++++++++++++++++++++++++--
> >>   drivers/gpu/drm/i915/i915_drv.h |  2 ++
> >>   drivers/gpu/drm/i915/intel_pm.c | 13 +++++++++++++
> >>   3 files changed, 48 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> >> index b93194cbd820..c6d30653d70c 100644
> >> --- a/drivers/gpu/drm/i915/i915_drv.c
> >> +++ b/drivers/gpu/drm/i915/i915_drv.c
> >> @@ -1063,6 +1063,29 @@ static void intel_sanitize_options(struct drm_i915_private *dev_priv)
> >>   	intel_gvt_sanitize_options(dev_priv);
> >>   }
> >>   
> >> +static void
> >> +intel_memdev_is_16gb_dimm(struct memdev_info *memdev_info,
> >> +			  u8 rank, u8 size, u8 width)
> >> +{
> >> +	bool found_16gb_dimm = false;
> >> +
> >> +	if (size == 16 && width == SKL_DRAM_WIDTH_X8 &&
> >> +	    rank == SKL_DRAM_RANK_SINGLE)
> >> +		found_16gb_dimm = true;
> >> +	else if (size == 32 && width == SKL_DRAM_WIDTH_X8 &&
> >> +		 rank == SKL_DRAM_RANK_DUAL)
> >> +		found_16gb_dimm = true;
> >> +	else if (size == 8 && width == SKL_DRAM_WIDTH_X16 &&
> >> +		 rank == SKL_DRAM_RANK_SINGLE)
> >> +		found_16gb_dimm = true;
> >> +	else if (size == 16 && width == SKL_DRAM_WIDTH_X16 &&
> >> +		 rank == SKL_DRAM_RANK_DUAL)
> >> +		found_16gb_dimm = true;
> >> +
> >> +	if (!memdev_info->is_16gb_dimm)
> >> +		memdev_info->is_16gb_dimm = found_16gb_dimm;
> >> +}
> > Pure functions are generally more fun. Would also make the function name
> > match the implementation.
> Are you suggesting to change the name to only "is_16gb_dimm" ?

I'm suggesting making it pure.

-- 
Ville Syrjälä
Intel