Messages in this thread | | | Subject | Re: [REGRESSION][BISECTED] 5.9-rc4 disables console on radeon | From | Christian König <> | Date | Wed, 9 Sep 2020 11:15:11 +0200 |
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Yes, that is an already known issue.
We are most likely going to revert the patch ASAP.
Christian.
Am 08.09.20 um 18:27 schrieb Mikael Pettersson: > Starting with linux-5.9-rc4, the Dell monitor on my desktop PC goes > black during boot > when the kernel activates the framebuffer console, except for this > error message shown > in the center of the screen: > > "Dell U2412M > The current input timing is not supported by the monitor display. Please > change your input timing to 1920x1200@60Hz or any other monitor > listed timing as per the monitor specifications. > <DVI symbol>" > > The monitor remains black until I reboot. > > All kernels up to and including 5.9-rc3 were Ok. A git bisect identified > > # first bad commit: [fc8c70526bd30733ea8667adb8b8ffebea30a8ed] > drm/radeon: Prefer lower feedback dividers > > as the culprit, and reverting that from -rc4 makes the console work again. > > Adding a bit of debugging code to that function shows: > > avivo_get_fb_ref_div: fb_div_new 136 fb_div_old 137 > avivo_get_fb_ref_div: fb_div_new 142 fb_div_old 143 > avivo_get_fb_ref_div: fb_div_new 136 fb_div_old 137 > avivo_get_fb_ref_div: fb_div_new 119 fb_div_old 120 > avivo_get_fb_ref_div: fb_div_new 136 fb_div_old 137 > > during boot, where "new" is what the commit above changed the code to compute, > and "old" is the value computed by the working code from rc3. > > The graphics card is a Radeon HD6450 silent model: > 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. > [AMD/ATI] Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM] (prog-if 00 > [VGA controller]) > _______________________________________________ > amd-gfx mailing list > amd-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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