Hi Fredrik, On Thu, Jul 19, 2018 at 10:14 PM Fredrik Noring <nor...@nocrew.org> wrote: > > > > so I added a sleep with > > > > > > > > + msleep(10000); > > > > I can't see where you added the sleep, but 10s seems excessive. > > If the real reason is the need to wait for an interrupt for > > ps3fb_sync_image(), > > then waiting for 40 ms should be sufficient? Or am I missing something? > > It's at the end of ps3fb_probe, as shown in the original post: > > https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-July/175771.html
Thanks, I had found that one in the mean time... > I thought 100 ms or so would work, but evidently it didn't. In fact, 1 s > for even 5 s didn't seem to work either. In any case, I would like to > develop a solution that does not need to sleep at all, so that will be my > first approach for a proper implementation. Hmm... > > > I suppose the problem is that it relies on interrupts for ps3fb_sync_image > > > > to regularly copy the image, hence without them the screen isn't > > > > updated to > > > > show kernel panics, etc. Perhaps one way to fix that is to implement the > > > > struct fb_tile_ops API, so that the console is synchronously updated? > > > > Would > > > > that be acceptable? > > > > > > I'm not sure if that would work or not. Maybe Geert is more familiar > > > with it. > > > > That sounds like a complex solution, slowing down the console a lot. > > Why would that be slow? I have implemented a similar technique for the > PlayStation 2 frame buffer, and (without any measurements at hand now) it > appears to be about as fast as is possible, and reasonably easy too. :) [...] OK, I retract my statement ;-) > > What about letting ps3fb register a panic notifier to sync the screen, like > > hyperv_fb does? > > That would not work with kernel freezes unfortunately. Debugging those with > nondeterministicly invisible kernel prints would be painful, I believe. Unfortunately AFAIK the PS3 doesn't have any other "synchronous" output we can use for debugging (like flashing the power LED). Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds