** Description changed: - We have a couple of laptop and desktop computers, all of them are cfl - platforms and all of them have cfl audio controller [8086:a348], and - these computers have different realtek codecs on them (alc256, alc255, - alc289 and ...). The hda driver takes too much time (3 secs - 8 secs) to - initialize on these machines. This problem never happened on kbl, skl, - bdl, ... before. + [Impact] + + We have a couple of laptop and desktop computers, all of them are cfl platforms + and all of them have cfl audio controller [8086:a348], and these computers have + different realtek codecs on them (alc256, alc255, alc289 and ...). The hda + driver takes too much time (3 secs - 8 secs) to initialize on these machines. + This problem never happened on kbl, skl, bdw, ... before. + + Sometimes this can make pulseaudio can't work well. + + pulseaudio starts, but the driver (as kernel modules) initialization has not + finished, then there is no valid sink in the pulseaudio. At this moment, some UI + Apps already start using pulseaudio to play sound, but users can't hear the sound + as expected. This problem never happened before, it is exposed on cfl platforms, + and all cfl platforms (with audio controller 8086:a348) have this problem. + + [Fix] + Set the polling mode can fix this problem, and this workaround is in the + mainline kernel. + + [Test Case] + Boot the machine and check the dmesg, from the hda log, we can see the driver + initialization is finished within 0.1s and pulseaudio works well. + + [Regression Potential] + No regression, this fix is only for CFL audio controller (8086:a348), and + in theory, polling mode is safe for all audio controllers, using interrupt + mode rather than polling mode on other platforms just wants to save polling + overhead for CPUs, since interrupt mode can't work well on CFL platform, we + have to use polling mode.
** Tags added: originate-from-1747356 somerville -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1758800 Title: hda driver initialization takes too much time on the machine with coffeelake audio controller [8086:a348] To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1758800/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
