(In reply to comment #14) > (In reply to comment #13) > > Do the PLL values in the log files I posted indicate a problem, or are they > > okay? > > [drm:radeon_compute_pll_avivo], 14875, pll dividers - fb: 23.8 ref: 2, post 8 > [drm:radeon_compute_pll_avivo], 7406, pll dividers - fb: 23.7 ref: 2, post 16 > > The display pll looks fine to me. The clock formula is: > > pixel_clock = (reference_frequency * feedback_divider) / (reference_divider > * post_divider) > > The reference frequency is 100 Mhz, so: > > (100Mhz * 23.8) / (2 * 8) = 148.75Mhz > > (100Mhz * 23.7) / (2 * 16) = 74.0625Mhz > > > > > How can you see the PLL values fglrx is using? > > You'd need to dump the PLL registers using radeonreg > (http://cgit.freedesktop.org/~airlied/radeontool/). > PPLL1 > 0x400 - ref div - bits 9:0 > 0x404 - fb div - whole part bits 26:16, fractional part bits 3:0 > 0x408 - post div - bits 6:0 > PPLL2 > 0x440 - ref div - bits 9:0 > 0x444 - fb div - whole part bits 26:16, fractional part bits 3:0 > 0x448 - post div - bits 6:0 > > e.g., ./radeonreg regmatch 0x400 I got the results with fglrx: PPLL1@50Hz: fb=23.7 ref=2 post=6 PPLL2@50Hz: fb=296.16 ref=7 post=6 PPLL1@23.976Hz: fb=23.7 ref=2 post=12 PPLL2@23.976Hz: fb=296.16 ref=7 post=6 PPLL2 does seem to be used as it does not change. PPLL1 has different values than with the radeon OSS driver. What does this mean?