#30 Some Xv resolutions screwed up.


Some Xv resolution / scaling combinations leave
artifacts at the left and right hand side borders.

For example 900x600 scaled to 1024x768.

Same both for YUY2 and YV12. As far as I can see, this
was present already in r23.

Preferrably, use "xvtestcard" to test.



  • Thomas Hellström

    Logged In: YES

    Andreas, do you have time to take a look at this?
    Otherwise, just reassign the bug!


  • Thomas Hellström

    • assigned_to: nobody --> sleeperse
  • Andreas Robinson

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    > Andreas, do you have time to take a look at this?

    Sure, no problem. Hmm, here is something weird: 900x600
    looks bad, 900x900 looks ok.

  • Andreas Robinson

    Logged In: YES

    Ok... I think the hardware runs out of bandwidth. If
    Y-interpolation is disabled in the overlay, the problem

    To help solve this problem, it might be necessary to look at
    VIAs driver.

    There is a group of functions in Share/Vidcle/overlay.c in
    CLEXF0047, called RejectOverlay_<chip-id>(). It calculates
    the bandwidth requirements from memory type, number of
    screens, resolution, refresh rate, overlay size etc and then
    decides whether the overlay can be used.

    So ... now what? Can we use it?

  • Thomas Hellström

    Logged In: YES

    Hmm, I'm not sure it's a bandwidth problem, because they
    appear like small transient black / white strikes across the

    Also there is an overlay reject function implemented for
    KM400 and CLE266 in via_video.c, where I have looked at VIAs
    modetable and implemented a conservative formula for what
    modes should be rejected. It should be more conservative
    than VIA's driver.

    Looks more like a HW bug to me? Any way to adjust the Y
    interpolation? Maybe we should test VIA's drivers and see
    how they behave. Also I've noticed that it seems to never
    occur when width is scaled down. Only when it is scaled up.


  • Andreas Robinson

    Logged In: YES

    I get coloured streaks on every other line on CLE266A. It's
    not random garbage but rather part of the video displayed in
    the wrong place.

    It is not possible to adjust the interpolation, besides
    turning it off.

    Assuming VIA designed and tested the CLE266 with standard TV
    resolutions, we could disable the interpolation when (width
    > 800) || (height > 600)?

  • Thomas Hellström

    Logged In: YES

    I haven't had time to try VIA's binaries yet. Have you
    tested those?
    If they exhibit the same problem, it is a good idea to
    disable the interpolation, but we might be able to do it in
    a smarter manner. This problem does not be present when
    scaling down, only when scaling up / not scaling at all
    under certain conditions.


  • Ivor Hewitt

    Ivor Hewitt - 2005-02-27
    • assigned_to: sleeperse --> ihewitt
  • John Wier

    John Wier - 2005-06-13

    Logged In: YES

    I was having a similar problem.

    In the problem case (1280x720p scaled up to 1400x1050) it
    looks like
    every other line of the left 25% of the display is getting
    swapped with
    the corresponding line from the right 25% of the display.

    It seems to me that you want to turn on the
    gdwUseExtendedFIFO value for the VT3259 chip
    id, as well as the CLE3122 chip id, if the display width is more
    than 1024.

    The change is localized to unichrome/via_swov.c, in the function

    if ((pVia->ChipId == PCI_CHIP_CLE3122) &&
    (pScrn->currentMode->HDisplay >
    1024)) {
    if ((pVia->ChipId == PCI_CHIP_CLE3122 || pVia->ChipId ==
    && (pScrn->currentMode->HDisplay >= 1024)) {

  • Luc Verhaegen

    Luc Verhaegen - 2005-10-21
    • assigned_to: ihewitt --> dwdeath
    • status: open --> closed-fixed
  • Luc Verhaegen

    Luc Verhaegen - 2005-10-21

    Logged In: YES

    "Striping" is caused by:
    hqvFilterCtl &= 0xfffdffff;

    Reopen bug if this was another issue.


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