[Intel-gfx] [PATCH] drm/i915: Get correct display clock on 945gm
ville.syrjala at linux.intel.com
Fri Jan 27 16:57:19 UTC 2017
On Fri, Jan 27, 2017 at 05:45:06PM +0100, Arthur Heymans wrote:
> Ville Syrjälä <ville.syrjala at linux.intel.com> writes:
> > On Fri, Jan 27, 2017 at 03:44:27PM +0100, Arthur Heymans wrote:
> > That indeed is what the docs say.
> > The code is tantalizingly close to the 915gm code now, so maybe
> > we could share it with a simple
> > if (IS_915GM(dev_priv))
> > return 320000;
> > else
> > return 333333;
> Agreed but it's the other way around ;)
Indeed. Apparently my brain can't reconcile the fact that the older part
> > Now if someone could figure out where to dig up the DDR and FSB clocks
> > we could also fix up the 190 vs. 200 MHz case...
> >> + default:
> >> + case GC_DISPLAY_CLOCK_190_200_MHZ:
> >> + return 200000;
> >> + }
> >> + }
> >> +}
> >> +
> Hmm that seems to be 915gm specific (always 200 on 945gm). According to
> "Mobile Intel® 915/910 Express Chipset: Datasheet", the only fsb/dram
> combo that has 190MHz is FSB: 533MHz, DDR333. All the other supported
> combos have 200Mhz set by that configuration.
Yeah. Unfortunately I couldn't find a solid source of FSB/DDR clock
information in the spec, apart from the actual strap pins but I can't
see any register that would reflect those. So I guess we'll just leave
it the way it is.
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