On 18.2.2014 2:18, Michal Šmucr wrote:
Hello, i'm fighting with audio playback problem on Beaglebone Black AM-3358. Class compilant USB soundcards with isochronous transfers. With DMA enabled in kernels 3.13.2 and 3.14-rc2 it has following symptoms. - it will stutter immediately after starts of playback - kworker thread shows about 80-90% CPU usage during playback - it presents with cppi41_dma_control warnings and traces, plus couple of transfer errors (i've enabled also CONFIG_DMADEVICES_DEBUG, so it dmesg is quite lengthy) http://vpub.smucr.cz/pub/bbb/debug/dmesg.log With force PIO at any tested kernel from 3.8.x to 3.14.x and DMA mode at 3.12.9 it is better, CPU load seems to be much lower, but it is not completely solved. Still during high interrupt load from other devices like NIC or second USB port, i'm having audio dropouts. Without any messages this time. I tested to apply following George Cherian's related patches http://marc.info/?l=linux-usb&m=139081552015728&w=2 usb: musb: musb_host: Enable ISOCH IN handling for AM335x host usb: musb: musb_cppi41: Make CPPI aware of high bandwidth transfers usb: musb: musb_cppi41: Handle ISOCH differently and not use the hrtimer and Adam Wozniak's http://marc.info/?l=linux-usb&m=139101388408467&w=2 "high cpu load on omap3 using musb"
I also tried to find something related in TI git tree and compile linux-next, but without luck.
Any tips, what to do next? Does anybody experienced same issue? Thanks, Michal -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
