Hi Jacek, Just to clarify: does the laptop works fine with other, non-rt-patched kernel? If yes, couldn't you copy existing config from /boot and make oldconfig based on that? cd linux-4.4.32 cp /boot/config-`uname -r` .config; make oldconfig Then enable CONFIG_PREEMPT_RT_FULL and configure the rest if needed. Simply enabling PREEMPT_RT_FULL is enough to get you started. You may have to do some tricks to get GUI with reasonable graphics though but this should give you runnable, stable system. I have some luck with this approach on a couple of machines so far. cheers, Piotr -----Original Message----- From: linux-rt-users-owner@xxxxxxxxxxxxxxx [mailto:linux-rt-users-owner@xxxxxxxxxxxxxxx] On Behalf Of Stéphane Ancelot Sent: 17 July 2017 07:21 To: Jacek Konieczny <jajcus@xxxxxxxxxx>; linux-rt-users@xxxxxxxxxxxxxxx Subject: Re: RT kernel on Acer laptop unreliable Hi, If you don't manage to achieve realtime, you have some wrong options in your kernel settings . Please share your kernel config. Regards, S.Ancelot Le 15/07/2017 à 19:43, Jacek Konieczny a écrit : > Hello, > > I need low and stable latency for audio processing. I use Guitarix, > Ardour and other jack-based applications. For anything else I would > use the regular kernel package from my distribution (PLD Linux), but > the latency spikes are unacceptable in some cases. That is why I have > been trying to use RT kernel, for a few months now… > > First I added the RT patch to the PLD Linux kernel package. I have > tried both the 4.4 and 4.9 kernel. Neither of them worked well. Then I > manually compiled a few vanilla 4.9.x kernels, just with the most > recent RT patch and with a configuration made from scratch (not to > copy any PLD mistakes). Still no luck. > > Most of the information I could find online is quite outdated or > incomplete, so I have really little idea what the proper configuration > of the RT kernel is or how to debug it. > > When the RT kernel works, it would provide quite acceptable latency – > I could get down to 8ms in jack with no significant xruns. > Unfortunately none of the RT kernels I tried would be reliable. With > little load the system would work for a few hours sometimes, but often > it would slow down and crash much earlier. With high load, e.g. when > trying to play some demanding game, the system would usually crash quite quickly. > > Sometimes it would just lock up hard with no warning and nothing would > work – not even magic sysrq. > Other times it would gradually slow down until it is not usable at all. > Sometimes I would be able to see some 'BUG' in dmesg, but rarely I > would be able to restart the system cleanly. > Sometimes only some subsystems would fail, while otherwise the system > still seems to work. It could be sound, mouse, keyboard or network > that doesn't work. > > System logs would contain some kernel BUGs/WARNINGs, but they would > often look generic and would not point to a specific problem (not for me). > > Today I have tried kernel 4.9.37 with the 4.9.35-rt25 patch. It failed > again, here are the kernel error logs: > > https://gist.github.com/Jajcus/494b79062b537269b49265ff3c50ee78 > > I have no idea how to properly debug the problem, even what data > should I collect to prepare a reasonable bug report. > > I have already upgraded laptop firmware to the latest available, I > have also played with some BIOS setup options. > > One thing that looks suspicious is the amount of time spent in IRQ 16 > handling, which is: 'idma64, i801_smbus, i2c_designware'. Also the > i801-smbus in i2c-designware-platform were first to fail when loaded. > Regular kernel (without PREEMPT_RT_FULL) seems to generate much lower > number of those interrupts. > > However, the system would crash even if the i2c modules are > blacklisted and not loaded. Getting rid of idma64 would not help much > either. IRQ 16 would not come any more, but the system would slow down and crash anyway. > > > Any idea what is the problem? > Any hints how to debug it? > > > Greets, > Jacek > -- > To unsubscribe from this list: send the line "unsubscribe > linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html ��.n��������+%������w��{.n�����{�����ǫ���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
