Re: Re: Geode driver question

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Re: Re: Geode driver question




I'm not sure that this is necessarily the 
case.
 
The dot clock used in XF86Config is never actually 
used to directly calculate the dot clock that the Geode uses.  The XFree86 
Geode driver (geode_driver.c) basically selects the appropriate mode from a set 
of modes provided in the Durango driver in gfx_disp.  These 
are:
 
320x200 @ 70Hz Doublescan
320x240 @ 75Hz Doublescan
400x300 @ 75Hz Doublescan
512x384 @ 75Hz Doublescan
640x400 @ 70Hz
640x480 @ 60Hz, 72Hz, 75Hz, 85Hz
800x600 @ 56Hz, 60Hz, 72Hz, 75Hz, 85Hz

1024x768@ 56Hz, 60Hz, 72Hz, 75Hz, 
85Hz1152x864 @ 75Hz
1280x1024 @60Hz, 75Hz, 85Hz
 
I don't believe that when using the above modes 
(which I believe came from National's orignal driver source) that at any time 
the dot clock actually goes into unsupported territory.  The changes I was 
suggesting simply allow a modeline to be specified in XF86Config that gets 
translated to one of the above modes in the geode_driver.c code.
 
Ed
<BLOCKQUOTE dir=ltr 
>
  ----- Original Message ----- 
  <DIV 
  >From: 
  bob 
  martin 
  To: <A title=xpert@xxxxxxxxxxx 
  href="">xpert@xxxxxxxxxxx 
  Cc: <A title=alanh@xxxxxxxxxxxxxxxxxxxx 
  href="">alanh@xxxxxxxxxxxxxxxxxxxx 
  Sent: Monday, December 09, 2002 3:40 
  PM
  Subject: Re: Re: Geode driver 
  question
  
  The minimum DOT clock for the Geode cores (GX1, SCxxx) is indeed 25.175 MHz 
  which limits our lowest official supported resolution to 640X480 @ 60 
  Hz. Unfortunately it's this middle region of display resolution that 
  isn't covered well as we have customers using either serial or PCI interfaces 
  driving lower resolutions displays, all the way down to 16 X 2 character LCD 
  displays.  We can't really officially supports any resolutions that 
  require a DOT clock below the minimum specified. 
  As a side note, the DOT clock has been used as low as 12 Mhz but the PLL 
  controlling this clock becomes unstable at this limit. 
  To answer the question on source for the Geode driver we are making period 
  submissions to the XFree development community and as well continuing to 
  evolve the framebuffer driver internally as it contains the extra 
  functionality to control the video process functions of the SC1200 device 
  regards 
  bob m / nat semi IA apps 
   Ed Anuff <ed@xxxxxxxxx> wrote: BR>> To: 
  > Sent: Sunday, December 08, 2002 10:47 PM> 
  Subject: Geode driver question>>> > I see from looking 
  at the source that the new Geode driver supports> several> > 
  modes such as 320x240 and 512x384 that I would like to make use of.> 
  > Unfortunately, I've been unable to create a modeline that works 
  withthem.> > Does anyone have the set of modelines that match 
  the resolutionssupported> > by the new driver?> 
  >> > Thanks> >> > Ed> 
  >>> _______________________________________________> 
  Xpert mailing list> Xpert@xxxxxxxxxxx> 
  http://XFree86.Org/mailman/listinfo/xpert>_______________________________________________Xpert 
  mailing listXpert@xxxxxxxxxxxxxxx://XFree86.Org/mailman/listinfo/xpert
  
  
  
  Do you Yahoo!?
  <BLOCKQUOTE 
  >Additional 
    changes necessary to make this work:In geode_driver.c:Line 1414: 
    minPitch = 320;Line 1445: PitchInc, 240, 1024,Otherwise, you'll 
    be able to display the resolution, but it will always bein virtual 
    screen with a minimum area of 640x480.However, with the change put 
    in, you end up dealing with the notorious GeodeXF86Config Virtual entry 
    wierdness, where the Virtual entry needs to be setto an odd setting like 
    "Virtual 513 384" or you get display problems.Because of the Virtual 
    stangeness, I'm not sure whether these changes shouldbe added to the 
    driver in CVS, but this may be of use to others, especiallysince the 
    Geode is often used in embedded PC's that need to display on 
    smallscreens with lower resolutions.Ed----- Original 
    Message -----From: "Ed Anuff" To: 
    Sent: Monday, December 09, 2002 10:38 AMSubject: 
    Re: Geode driver question> I think that I found the 
    problem. The minimun clock frequency in line 844> of geode_driver.c 
    is too high to allow the lower resolutions to 
    beaccepted:>> static ClockRange GeodeClockRange = { NULL, 
    25175, 135000, 0, FALSE, TRUE,> 1, 1, 0 };>> Changing 
    the minimum clock frequency to 1 solves the problem:>> static 
    ClockRange GeodeClockRange = { NULL, 1, 135000, 0, FALSE, TRUE, 
    1,1,> 0 };>> Clearly, this is not a valid lower 
    boundery, but it solves the problem,and> it looks like other 
    drivers are taking the same approach of setting a> minimum of 0 or 
    1.>> Also, the HorizSync range in XF86Config will need to 
    allow a lower minimum> value so something like 10-60 will be 
    necessary.>> Hope this helps others,>> 
    Ed>>> ----- Original Message -----> From: "Ed 
    Anuff" <<A 
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    Mail Plus - Powerful. Affordable. <A 
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