[Intel-gfx] [Patch] DRM/I915: Don't set the DPLL_MD multipler for LVDS output

[Eric Anholt]

On Mon, 2009-08-31 at 14:13 +0800, yakui.zhao at intel.com wrote:
> From: Zhao Yakui <yakui.zhao at intel.com>
> 
> When the output device is LVDS, maybe the pixel clock of adjusted_mode will be 
> less than that in mode. In such case it will set the incorrect multipler factor
> in DPLL_MD register.
> So it is unnecessary to set dpll_md_reg when the output type is LVDS.

This seems wrong.  Now you leave whatever junk is currently in the
register there?

Seems like the right answer is:
if (IS_THING_WITH_DPLL_MD && is_sdvo) {
	I915_WRITE(dpll_md_reg, sdvo_pixel_multiply)
} else {
	I915_WRITE(dpll_md_reg, 0); // whatever means "multiply by one"
}

Also makes the change clear, because looking at it I figured you were
trying to solve an SDVO LVDS problem.

-- 
Eric Anholt
eric at anholt.net                         eric.anholt at intel.com


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