path: root/sound/usb/6fire/pcm.h
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authorClemens Ladisch <clemens@ladisch.de>2013-08-08 11:24:55 +0200
committerTakashi Iwai <tiwai@suse.de>2013-08-08 11:37:34 +0200
commit57e6dae1087bbaa6b33d3dd8a8e90b63888939a3 (patch)
tree3f96789f16329d9053f02c0699a3eb48b4f28e62 /sound/usb/6fire/pcm.h
parentddb6b5a964371e8e52e696b2b258bda144c8bd3f (diff)
ALSA: usb-audio: do not trust too-big wMaxPacketSize values
The driver used to assume that the streaming endpoint's wMaxPacketSize value would be an indication of how much data the endpoint expects or sends, and compute the number of packets per URB using this value. However, the Focusrite Scarlett 2i4 declares a value of 1024 bytes, while only about 88 or 44 bytes are be actually used. This discrepancy would result in URBs with far too few packets, which would not work correctly on the EHCI driver. To get correct URBs, use wMaxPacketSize only as an upper limit on the packet size. Reported-by: James Stone <jamesmstone@gmail.com> Tested-by: James Stone <jamesmstone@gmail.com> Cc: <stable@vger.kernel.org> # 2.6.35+ Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/6fire/pcm.h')
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