Re: [PATCH] matroxfb: another attempt to rectify jitter (G450/G550)

["Paul A. Clarke" <pc@us.ibm.com>]

Ville Syrjälä wrote:
> On Tue, Jan 30, 2007 at 02:22:37PM -0600, Paul A. Clarke wrote:
> snip...
>> +				/* DVI PLL preferred for frequencies up to panellink max, standard PLL
>> otherwise */
>> +				if (fout >= MINFO->max_pixel_clock_panellink) tmp = 0;
>> +				else tmp =
>> +					M1064_XDVICLKCTRL_DVIDATAPATHSEL |
>> +					M1064_XDVICLKCTRL_C1DVICLKSEL |
>> +					M1064_XDVICLKCTRL_C1DVICLKEN |
> 
> Shouldn't this check which CRTC is driving the DVI?

If I read the code correctly, I don't see any way this code gets invoked for CRTC2.  __g450_setclk() is only called by 
matroxfb_g450_setclk(), which is in turn called in 8 places:
- 2 with pll == M_VIDEO_PLL (a different case in the enclosing switch)
- 1 with pll == M_SYSTEM_PLL (a different case in the enclosing switch)
- 3 which if (m->crtc != MATROXFB_SRC_CRTC1) then pll == M_VIDEO_PLL
- 2 with M_PIXEL_PLL_A and M_PIXEL_PLL_B (once each) at init time to set legacy VGA clocks with both CRTCs disabled

>> +					M1064_XDVICLKCTRL_DVILOOPCTL |
>> +					M1064_XDVICLKCTRL_P1LOOPBWDTCTL;
>> +				matroxfb_DAC_out(PMINFO M1064_XDVICLKCTRL,tmp);
>>    				matroxfb_DAC_out(PMINFO M1064_XPWRCTRL, xpwrctrl);
>>
>>    				matroxfb_DAC_unlock_irqrestore(flags);

I'll also admit that my level of expertise here is not what I'd prefer, but my (perhaps suboptimal) testing showed good results.
-- 
Regards,
Paul Clarke

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