Hi, On Wed, Apr 30, 2025 at 10:05:44AM -0700, Doug Anderson wrote: > On Wed, Apr 30, 2025 at 6:28 AM Nick Bowler <nbow...@draconx.ca> wrote: > > On Mon, Apr 28, 2025 at 01:40:25PM -0700, Doug Anderson wrote: > > > On Sun, Apr 20, 2025 at 9:26 PM Nick Bowler <nbow...@draconx.ca> wrote: > > > > I recently noticed that on current kernels I lose video output from > > > > my Blackbird's AST2500 BMC after a reboot > > [...] > > > > ce3d99c8349584bc0fbe1e21918a3ea1155343aa is the first bad commit > > > > commit ce3d99c8349584bc0fbe1e21918a3ea1155343aa > > > > Author: Douglas Anderson <diand...@chromium.org> > > > > Date: Fri Sep 1 16:39:53 2023 -0700 > > > > > > > > drm: Call drm_atomic_helper_shutdown() at shutdown time for misc > > > > drivers [...] > Do you happen to have anything that's just a normal HDMI sink, like a > TV or a standard monitor that takes HDMI?
I can probably find something else to try later. > > To clarify, there is no boot failure. There is just no video output > > after rebooting. I can then boot Linux again by any method that works > > without being able to see the screen, and then everything is fine once > > I do that. > > Super weird. So every other boot works? On a new/broken kernel, every time I run "reboot" the video turns off when Linux does whatever it does to make the system restart. The video comes on again if I manage to boot it up again. The problem is that I have to do that without using the screen. So I can boot Linux via the serial port, or via the BMC web interface, or by just typing on the keyboard without seeing what is happening. > I guess I'd be interested in other types of tests to see what's going > on. Aside from trying some other, more standard HDMI sinks, I'd love > to see the results of: > > 1. HDMI is supposed to be hotpluggable. If you've got a boot where the > display isn't working, what if you unplug the HDMI and plug it back > in. Does it fix it? Unplugging/replugging the cable when the video is off after rebooting does not cause it to start working again. > 2. Does the hotplug experience change if you boot with the revert? > AKA: boot up with the revert (so everything is working normally), > unplug HDMI, wait a few seconds, plug HDMI back in? Is this different > than #1? I have certainly never noticed any problem related to hot plugging while the video output is working but this is not something I ever normally do. I can try it later. > 3. What about if you fully power off and then power on? Does the > display work reliably in this case, or are things different between > ToT and with the revert? There is never any problem with the video output if I fully power off/on the system. The problem only occurs on a reboot. > 4. What about if you fully power off, unplug the HDMI, wait a few > seconds, plug the HDMI, and power on? Does that work? Are things > different between ToT and with the revert? Again there is never any problem if I fully power off/on the system. Thanks, Nick
