Hi, Radeon commit 72feaa37ea07620f5f2ead438dbc72a1c8883cd3 ("prefer lower ref dividers..") causes flicker here, on a Radeon HD 3450 connected to an Apple 30" cinema display. The PLL settings are different before and after the patch, so that's a likely culprit. Before (working): http://dev.laptop.org/~cjb/xorg-noflicker.log After (broken): http://dev.laptop.org/~cjb/xorg-flicker.log In particular, before: best_freq: 268000000 best_feedback_div: 1072 best_ref_div: 27 best_post_div: 4 (II) RADEON(0): crtc(0) PLL : refdiv 27, fbdiv 0x430(1072), pdiv 4 and after: best_freq: 268000000 best_feedback_div: 268 best_ref_div: 9 best_post_div: 3 (II) RADEON(0): crtc(0) PLL : refdiv 9, fbdiv 0x10C(268), pdiv 3
Alex and I tried some PLL changes that had different results. Broken (post-patch): 268/9/3 Fixed (pre-patch): 1072/27/4 Almost working, still occasional flicker: 804/27/3 The 804/27/3 was reached via: <agd54> try changing line 232 of radeon_crtc.c <agd5f> change the '<' to '>' } else if ((flags & RADEON_PLL_PREFER_LOW_REF_DIV) && (ref_div < best_ref_div)) {
fixed in git: 92ee21df344a989778e37369c7beb3904a00ead6
> fixed in git: > 92ee21df344a989778e37369c7beb3904a00ead6 This gets me back to 804/27/3, which means that I still have the flicker regression behavior. Alex says he'll fix up the patch, and I'll retest then.
Mea culpa, stale driver. This correctly finds 1072/27/4, closing.
I'm seeing something that may be the "occasional flicker" behavior. I suspect it may be PLL-related, because I am able to fix it with the radeonhd driver by using the "AtomBIOS" "pll=on" option. How can I determine if the driver version in Fedora 10 includes this fix? Thanks!
(In reply to comment #5) > I'm seeing something that may be the "occasional flicker" behavior. I > suspect it may be PLL-related, because I am able to fix it with the > radeonhd driver by using the "AtomBIOS" "pll=on" option. > > How can I determine if the driver version in Fedora 10 includes this > fix? Do you have a 2560x1600 monitor? This bug and fix really only relates to high dot clocks. If you are using a different monitor please file a new bug and attach your xorg log and config.
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