• David Brownell's avatar
    [PATCH] USB: ehci-hcd, partial VIA workaround · f0a71006
    David Brownell authored
    This patch resolves a FIXME, which happens to make many of
    the VIA problems act significantly less severe.  The change
    defers unlinking any QH that just became idle, since it's not
    unlikely it'll be used again before many milliseconds pass.
    
    It reduces the number of unlink interrupts (IAA), and means
    fewer re-activation issues.  Like: newly queued TDs being
    all or partially processed before the QH gets de-activated.
    The VIA hardware seems to have some problems in those cases.
    (Which are extremely common on 2.4 kernels, and less so on
    2.5 because usb-storage streams data much better now.)
    
    It also starts tracking the "lost IAA" errors that I see on
    at least one VT8235 motherboard.  It shows in the "registers"
    sysfs file.  It'd be good to know if it's just my hardware
    that has this problem, or if other folk also see it.
    f0a71006
ehci-dbg.c 17 KB