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@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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