When I play something, depending on the buffer length and the period length, sometimes ALSA complaints about a wrong hw_pointer value. pcm_hw_pointer() returns the right value and the irq handler (not shown below) calls snd_pcm_period_elapsed() only when the period is done. I can't understand what happens. Below I report the first burst since I started playing something. 1.7MB transferred, buffer_size=32768 frames, period_size=1323 frames (25 periods). fr=the position (in frames) inside the buffer. I choosed that setting because it makes alsa to spit the warning sooner than others. It seems to happen when the period size is not a multiple of the buffer size, but I failed to find a relation between bufsz/persz and the points where it prints the errors.
pcm_hw_pointer=1699968 fr=31776 pcm_hw_pointer=1704064 fr=32 pcm_hw_pointer=1704064 fr=32 pcm_hw_pointer=1709312 fr=1344 pcm_hw_pointer=1709312 fr=1344 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -1, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1714560 fr=2656 pcm_hw_pointer=1714560 fr=2656 pcm_hw_pointer=1714560 fr=2656 pcm_hw_pointer=1714560 fr=2656 pcm_hw_pointer=1714560 fr=2656 pcm_hw_pointer=1719936 fr=4000 pcm_hw_pointer=1719936 fr=4000 pcm_hw_pointer=1719936 fr=4000 pcm_hw_pointer=1725184 fr=5312 pcm_hw_pointer=1725184 fr=5312 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -2, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1730432 fr=6624 pcm_hw_pointer=1730432 fr=6624 pcm_hw_pointer=1730432 fr=6624 pcm_hw_pointer=1730432 fr=6624 pcm_hw_pointer=1735808 fr=7968 pcm_hw_pointer=1735808 fr=7968 pcm_hw_pointer=1735808 fr=7968 pcm_hw_pointer=1741056 fr=9280 pcm_hw_pointer=1741056 fr=9280 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -3, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1746304 fr=10592 pcm_hw_pointer=1746304 fr=10592 pcm_hw_pointer=1746304 fr=10592 pcm_hw_pointer=1746304 fr=10592 pcm_hw_pointer=1751680 fr=11936 pcm_hw_pointer=1751680 fr=11936 pcm_hw_pointer=1751680 fr=11936 pcm_hw_pointer=1756928 fr=13248 pcm_hw_pointer=1756928 fr=13248 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -4, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1762176 fr=14560 pcm_hw_pointer=1762176 fr=14560 pcm_hw_pointer=1762176 fr=14560 pcm_hw_pointer=1762176 fr=14560 pcm_hw_pointer=1767552 fr=15904 pcm_hw_pointer=1767552 fr=15904 pcm_hw_pointer=1767552 fr=15904 pcm_hw_pointer=1772800 fr=17216 pcm_hw_pointer=1772800 fr=17216 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -5, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1778048 fr=18528 pcm_hw_pointer=1778048 fr=18528 pcm_hw_pointer=1778048 fr=18528 pcm_hw_pointer=1778048 fr=18528 pcm_hw_pointer=1783424 fr=19872 pcm_hw_pointer=1783424 fr=19872 pcm_hw_pointer=1783424 fr=19872 pcm_hw_pointer=1788672 fr=21184 pcm_hw_pointer=1788672 fr=21184 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -6, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1793920 fr=22496 pcm_hw_pointer=1793920 fr=22496 pcm_hw_pointer=1793920 fr=22496 pcm_hw_pointer=1793920 fr=22496 pcm_hw_pointer=1799296 fr=23840 pcm_hw_pointer=1799296 fr=23840 pcm_hw_pointer=1799296 fr=23840 pcm_hw_pointer=1804544 fr=25152 pcm_hw_pointer=1804544 fr=25152 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -7, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1809792 fr=26464 pcm_hw_pointer=1809792 fr=26464 pcm_hw_pointer=1809792 fr=26464 pcm_hw_pointer=1809792 fr=26464 pcm_hw_pointer=1815168 fr=27808 pcm_hw_pointer=1815168 fr=27808 pcm_hw_pointer=1815168 fr=27808 pcm_hw_pointer=1820416 fr=29120 pcm_hw_pointer=1820416 fr=29120 ALSA ../alsa-kernel/core/pcm_lib.c:155: Unexpected hw_pointer value (stream = 0, delta: -8, max jitter = 16384): wrong interrupt acknowledge? pcm_hw_pointer=1825664 fr=30432 pcm_hw_pointer=1825664 fr=30432 pcm_hw_pointer=1825664 fr=30432 pcm_hw_pointer=1825664 fr=30432 pcm_hw_pointer=1831040 fr=31776 pcm_hw_pointer=1831040 fr=31776 pcm_hw_pointer=1831040 fr=31776 pcm_hw_pointer=1835136 fr=32 -- Bye. Giuliano. ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. Download today and enter to win an XBOX or Visual Studio .NET. http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01 _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
