C-Media / usb device bug ?

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(sorry if this come twice, i think i miss posted first one)

Hi,
 I'm working in a multi-capture application with alsa and i discovered
if i attach two "c-media usb headphone set" adapters to an usb hub which
is attached to my computer when i try to read from the two devices the
first one read (also open) errors with (-77) bad file descriptor status
and the other one keep working. When i attach the two devices directly to
the usb connectors (without hub) all works fine, the two devices can be
read at the same time. I proved Hubs version 1.0 and 2.0 .

Regards
Pablo


 This is the /proc/asound/cards when i attach them to the hub:
(yes i also have an intel device)

0 [ICH6           ]: ICH4 - Intel ICH6
                      Intel ICH6 with AD1980 at 0xd0201000, irq 20
 1 [default        ]: USB-Audio - C-Media USB Headphone Set
                      C-Media USB Headphone Set   at usb-0000:00:1d.1-1.3,
full speed
 2 [default_1      ]: USB-Audio - C-Media USB Headphone Set
                      C-Media USB Headphone Set   at usb-0000:00:1d.1-1.2,
full speed

and this is when i attach them directly to the computer:
0 [ICH6           ]: ICH4 - Intel ICH6
                      Intel ICH6 with AD1980 at 0xd0201000, irq 20
 1 [default        ]: USB-Audio - C-Media USB Headphone Set
                      C-Media USB Headphone Set   at usb-0000:00:1d.0-1,
full speed
 2 [default_1      ]: USB-Audio - C-Media USB Headphone Set
                      C-Media USB Headphone Set   at usb-0000:00:1d.3-2,
full speed

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