| Message ID | bug-96789-502@http.bugs.freedesktop.org/ (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
https://bugs.freedesktop.org/show_bug.cgi?id=96789 --- Comment #1 from Christian König <deathsimple@vodafone.de> --- Well that is a rather special case. The monitor needs a very precise timing to work reliable and even with the higher ref/post dividers we don't hit it completely correct. Not sure what to do here, cause raising the limit will certainly break others again.
https://bugs.freedesktop.org/show_bug.cgi?id=96789 --- Comment #2 from Benjamin Herrenschmidt <benh@kernel.crashing.org> --- Will it ? I mean, it works with every other driver under the sun ;-) Do you have ways to know what AMD windows driver picks ? That could be a reasonable choice for the Linux one...
https://bugs.freedesktop.org/show_bug.cgi?id=96789
Martin Peres <martin.peres@free.fr> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |MOVED
Status|NEW |RESOLVED
--- Comment #3 from Martin Peres <martin.peres@free.fr> ---
-- GitLab Migration Automatic Message --
This bug has been migrated to freedesktop.org's GitLab instance and has been
closed from further activity.
You can subscribe and participate further through the new bug through this link
to our GitLab instance: https://gitlab.freedesktop.org/drm/amd/issues/723.
--- a/drivers/gpu/drm/radeon/radeon_display.c +++ b/drivers/gpu/drm/radeon/radeon_display.c @@ -953,7 +953,7 @@ static void avivo_get_fb_ref_div(unsigned nom, unsigned den, unsigned post_div, unsigned *fb_div, unsigned *ref_div) { /* limit reference * post divider to a maximum */ - ref_div_max = max(min(100 / post_div, ref_div_max), 1u); + ref_div_max = max(min(128 / post_div, ref_div_max), 1u); /* get matching reference and feedback divider */
https://bugs.freedesktop.org/show_bug.cgi?id=96789 Bug ID: 96789 Summary: Black screen with R9 290 and Apple Cinema Display 23" Product: DRI Version: unspecified Hardware: x86-64 (AMD64) OS: Linux (All) Status: NEW Severity: normal Priority: medium Component: DRM/Radeon Assignee: dri-devel@lists.freedesktop.org Reporter: benh@kernel.crashing.org With Radeon (any recent distro version including upstream 4.7-rc5), my Apple Cinema Display 23" gives a black screen when radeon loads. The monitor is a fairly old DVI LCD 1920x1200x60. It has a fixed timing, ie, no scaler. It used to work with earlier versions of radeons but I haven't used it on a Linux machine for a couple of hears at least. It works using the agd5f's current amdgpu, but not upstream which doesn't support the HAWAII. I isolated the difference that makes it work to the PPLL setting. This one liner fixes it: *ref_div = min(max(DIV_ROUND_CLOSEST(den, post_div), 1u), ref_div_max); Here's a log of the working vs. non-working versions of the calculations in radeon_compute_pll_avivo(). Note that when I did these, I also changed radeon's max_feedback_div to match amdgpu's value of 0xfff instead of 0x7ff in current radeon, though that didn't impact the results. [ 3.471131] fb_div_min/max=4/4095 pll_flags=400 [ 3.471132] by 10 ! fb_div_min/max=40/40950 [ 3.471133] ref_div_min=2 (from 0/2) [ 3.471133] ref_div_max=1023 (from 0/1023) [ 3.471134] vco_min/max=600000/1200000 [ 3.471134] post_div_min/max=4/7 [ 3.471135] initial nom=153970, den=2700 [ 3.471136] reduced nom=15397, den=270 [ 3.471136] - trying post_div 4, ref_div_max=32 [ 3.471137] tentative ref_div=32m, fb_div=7299 [ 3.471137] adjusted ref_div=32m, fb_div=7299 [ 3.471138] diff=7, diff_best=-1 [ 3.471138] - trying post_div 5, ref_div_max=25 [ 3.471139] tentative ref_div=25m, fb_div=7128 [ 3.471139] adjusted ref_div=25m, fb_div=7128 [ 3.471139] diff=6, diff_best=7 [ 3.471140] - trying post_div 6, ref_div_max=21 [ 3.471140] tentative ref_div=21m, fb_div=7185 [ 3.471141] adjusted ref_div=21m, fb_div=7185 [ 3.471141] diff=6, diff_best=6 [ 3.471141] - trying post_div 7, ref_div_max=18 [ 3.471142] tentative ref_div=18m, fb_div=7185 [ 3.471142] adjusted ref_div=18m, fb_div=7185 [ 3.471150] diff=6, diff_best=6 [ 3.471150] post_div_best=7 [ 3.471151] - trying post_div 7, ref_div_max=18 [ 3.471151] tentative ref_div=18m, fb_div=7185 [ 3.471152] adjusted ref_div=18m, fb_div=7185 [ 3.471153] [drm:amdgpu_pll_compute] 153970 - 153960, pll dividers - fb: 239.5 ref: 6, post 7 Now this is with radeon *NOTE: I have bumped the max fb div to the same as AMD GPU when taking that trace but that had no effect: [ 4.718126] fb_div_min/max=4/4095 pll_flags=410 [ 4.718126] by 10 ! fb_div_min/max=40/40950 [ 4.718127] ref_div_min=2 (from 0/2) [ 4.718128] ref_div_max=1023 (from 0/1023) [ 4.718128] vco_min/max=600000/1200000 [ 4.718129] post_div_min/max=4/7 [ 4.718129] initial nom=153970, den=2700 [ 4.718130] reduced nom=15397, den=270 [ 4.718130] - trying post_div 4, ref_div_max=25 [ 4.718131] tentative ref_div=25m, fb_div=5703 [ 4.718131] adjusted ref_div=25m, fb_div=5703 [ 4.718132] diff=11, diff_best=-1 [ 4.718133] - trying post_div 5, ref_div_max=20 [ 4.718133] tentative ref_div=20m, fb_div=5703 [ 4.718133] adjusted ref_div=20m, fb_div=5703 [ 4.718134] diff=11, diff_best=11 [ 4.718134] - trying post_div 6, ref_div_max=16 [ 4.718135] tentative ref_div=16m, fb_div=5474 [ 4.718135] adjusted ref_div=16m, fb_div=5474 [ 4.718136] diff=14, diff_best=11 [ 4.718136] - trying post_div 7, ref_div_max=14 [ 4.718136] tentative ref_div=14m, fb_div=5589 [ 4.718137] adjusted ref_div=14m, fb_div=5589 [ 4.718137] diff=12, diff_best=11 [ 4.718138] post_div_best=5 [ 4.718138] - trying post_div 5, ref_div_max=20 [ 4.718139] tentative ref_div=20m, fb_div=5703 [ 4.718139] adjusted ref_div=20m, fb_div=5703 [ 4.718141] [drm:radeon_compute_pll_avivo] 153970 - 153980, pll dividers - fb: 570.3 ref: 20, post 5 The modeline is: Modeline 55:"1920x1200" 60 153970 1920 1968 2000 2080 1200 1203 1209 1235 0x48 0x9 And is consistent between the 2 drivers (different mode number but same values).