Bug 28901

Summary: ATI driver returns dim screen at color depth 16
Product: xorg Reporter: Wai Ling Tsang <simotsa>
Component: Driver/RadeonAssignee: xf86-video-ati maintainers <xorg-driver-ati>
Status: RESOLVED DUPLICATE QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium    
Version: 7.5 (2009.10)   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description Wai Ling Tsang 2010-07-03 17:56:14 UTC 
In xorg 7.0, the open source driver works fine at color depth 16.  However, after I upgraded to 7.5, using the same Driver settings, the screen will go unreasonably dim.

As suggested in other forum (i.e. https://bugzilla.redhat.com/show_bug.cgi?id=554967), I have to disable the gamma set for color depth 16, as follows:

static void
radeon_crtc_gamma_set(xf86CrtcPtr crtc, uint16_t *red, uint16_t *green,
                      uint16_t *blue, int size)
{
    RADEONCrtcPrivatePtr radeon_crtc = crtc->driver_private;
    ScrnInfoPtr         pScrn = crtc->scrn;
    int i, j;

    if (0/*pScrn->depth == 16*/) {
        for (i = 0; i < 64; i++) {
            if (i <= 31) {
                for (j = 0; j < 8; j++) {
                    radeon_crtc->lut_r[i * 8 + j] = red[i] >> 6;
                    radeon_crtc->lut_b[i * 8 + j] = blue[i] >> 6;
                }
            }
...
Comment 1 Alex Deucher 2010-07-05 21:16:46 UTC 

*** This bug has been marked as a duplicate of bug 28494 ***

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.