Takashi Iwai wrote: > Patrick May reported that his sound card with CMI8378 chip causes a > crash / reboot when accessing the MIDI port that isn't actually > present on the board. [...] > Although fixing the unexpected reboot would be the best solution, it's > not so trivial to identify the cause. There was a similar problem in the CMI8788 driver: https://git.kernel.org/linus/f1bc07af9a9e https://bugtrack.alsa-project.org/alsa-bug/view.php?id=4496 (does this still exist?) When reading a register repeatedly, the chip sometimes does not complete the PCI transaction. Apparently, mainboard PCI chipsets ignore this error, but PCIe/PCI bridges generate a machine check exception in this case. When writing MIDI data to a MPU-401-like device, the driver regularly polls the status register. I expect that this will blow up with any C-Media chip on a card with a PCIe/PCI bridge, regardless of whether a MIDI port exists. (I wonder if this can be triggered with snd_pcm_avail() in a loop. Maybe it happens only for byte accesses, or nobody has yet found out.) > As default, the MPU port is still enabled It might be a good idea to disable it by default if the parent bridge is an ASM1083. Regards, Clemens _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
