• Daniel Mack's avatar
    ALSA: snd-usb: try harder to find USB_DT_CS_ENDPOINT · 7b475d0e
    Daniel Mack authored
    commit ebfc594c
    
     upstream.
    
    The USB_DT_CS_ENDPOINT class-specific endpoint descriptor is usually
    stuffed directly after the standard USB endpoint descriptor, and this is
    where the driver currently expects it to be.
    
    There are, however, devices in the wild that have it the other way
    around in their descriptor sets, so the USB_DT_CS_ENDPOINT comes
    *before* the standard enpoint. Devices known to implement it that way
    are "Sennheiser BTD-500" and Plantronics USB headsets.
    
    When the driver can't find the USB_DT_CS_ENDPOINT, it won't be able to
    change sample rates, as the bitmask for the validity of this command is
    storen in bmAttributes of that descriptor.
    
    Fix this by searching the entire interface instead of just the extra
    bytes of the first endpoint, in case the latter fails.
    Signed-off-by: default avatarDaniel Mack <zonque@gmail.com>
    Reported-and-tested-by: default avatarTorstein Hegge <hegge@resisty.net>
    Reported-and-tested-by: default avatarYves G <alsa-user@vivigatt.com>
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    7b475d0e
stream.c 13.2 KB