Re: dual head r128

On Thu, 12 Oct 2000, Hendricks, Kevin wrote:

Hi,

quoted

the patch breaks the calculations for the x86 cards
(thats the reason why its not in the xfree cvs), so don't expect to get
sane values for the x86 card. (aty128fb has the same problem as well btw)

Why?  This should not be unless the bios on the x86 card never initializes
the card in any way.  If the bios does do some basic initialization, the
patch should work just as well for an x86 card as a ppc one if the main
clock rate is the same.  If the main clock rate is different, as long as
you can find out what it is, reading and calculating the  timings from
those register settings really should work generically, shouldn't it?

The reference frequency isn't the same in all cards, your patch assumes that
  /* Assume REF clock is 2950 (in units of 10khz) */
  /* and that all pllclk must be between 125 Mhz and 250Mhz */

From the comment in r128_driver.c you can see that the possible values are

29.50MHz, 28.63MHz, or 14.32MHz.

  /* These probably aren't going to work for
     the card you are using.  Specifically,
     reference freq can be 29.50MHz,
     28.63MHz, or 14.32MHz.  YMMV. */

Most of the ppc r128 cards have a reference frequency of 29.50MHz so the
code works but i heard that some of the new ones have different reference
freq.

  Kostas.


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