linux/sound
Clemens Ladisch 57e6dae108 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>
2013-08-08 11:37:34 +02:00
..
aoa
arm
atmel
core
drivers
firewire
i2c
isa
mips
oss
parisc
pci
pcmcia
ppc
sh
soc
sparc
spi
synth
usb ALSA: usb-audio: do not trust too-big wMaxPacketSize values 2013-08-08 11:37:34 +02:00
ac97_bus.c
Kconfig
last.c
Makefile
sound_core.c
sound_firmware.c