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Re: 2.6.15-1-sparc64 issues on blade 100

On Feb 14, 2006, at 11:42 AM, Dave Love wrote:

My XF86Config-4 does still have the old

        Option          "reference_clock" "28.636 Mhz"

though.  Presumably that should be irrelevant now, should it?


Dave:

	I've been dragging that line around in my X config file for
quite awhile.  So I decided to run an experiment this morning and see
what happened if I deleted it.   Lo and behold, I got diagonal stripes
moving up (or down) quickly, as if the VHOLD and HSYNC on an old TV got
played with by a 4 year old nephew. Buried in the X log was the following 
line:

	(--) ATI(0): Reference clock 14.318 MHz.
Now this number was familiar; I had just seen it on web page describing the 
options for the ATI driver for Xfree:

	http://www.xfree86.org/~dawes/4.3.0/ati5.html#26
But the number 28.636 still seemed funny, it was mentioned in the web page as a typical value, but when I took the cover off of my Blade 100 to check on the clock frequency that the kernel ATY FB driver needed, I did not recall seeing that clock frequency there.
So I took a peek at the reference clock chip (X7) and it is a 29.4 Mhz clock. 

So I would say:

	1) An 'Option 	"reference_clock" "XXX Mhz"' line is needed as the X
driver sets the reference clock to a default value when a PC BIOS is not present. The default is wrong for my machine and is likely wrong for all Blade 100's. 

	2) At least some SPARC Blade 100's have a 29.4 Mhz reference clock.
3) The difference between 28.636 and 29.4 Mhz is small enough to be ignored 
	for large divisors, but could present a problem for small divisors.
4) It could be that no Blade 100 uses a 28.636 Mhz reference clock and that someone tried the next "typical" value on the list and stopped experimenting since it worked and never took the lid off to see if the value reflected what 
	the hardware was doing.
Can any other owners of SPARC Blade 100's out there pop the lid off their machines and look at numbers printed on the two clock crystals near the RageXL chip? On my machine, 
the crystal is labeled X7.

-- Luis

PS:  If you need a picture, I have one I can send you if you need it.
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