• Benjamin Herrenschmidt's avatar
    [PATCH] USB: Fix USB suspend/resume crasher (#2) · 8de98402
    Benjamin Herrenschmidt authored
    This patch closes the IRQ race and makes various other OHCI & EHCI code
    path safer vs. suspend/resume.
    I've been able to (finally !) successfully suspend and resume various
    Mac models, with or without USB mouse plugged, or plugging while asleep,
    or unplugging while asleep etc... all without a crash.
    
    Alan, please verify the UHCI bit I did, I only verified that it builds.
    It's very simple so I wouldn't expect any issue there. If you aren't
    confident, then just drop the hunks that change uhci-hcd.c
    
    I also made the patch a little bit more "safer" by making sure the store
    to the interrupt register that disables interrupts is not posted before
    I set the flag and drop the spinlock.
    
    Without this patch, you cannot reliably sleep/wakeup any recent Mac, and
    I suspect PCs have some more sneaky issues too (they don't frankly crash
    with machine checks because x86 tend to silently swallow PCI errors but
    that won't last afaik, at least PCI Express will blow up in those
    situations, but the USB code may still misbehave).
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
    8de98402
ohci-hcd.c 26 KB