Re: [LAU] No duplex mode with the EHCI driver and USB hub. Is the problem solved?

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To: <linux-audio-user@...>
Date: Wednesday, November 9, 2011 - 11:39 am

Brendan Jones wrote:

There seems to be a miserunderstanding.

The Linux EHCI driver has (and has always had) a bug in the TT scheduler
that makes it unable to allocate enough bandwidth for more than one
stream for full-speed audio devices connected through a high-speed hub.

The mentioned patch fixes this bug (mostly).

As long as the patch didn't exist, a workaround was to connect the
device directly to the computer (so that not EHCI but another controller
would be used). This workaround is not possible with recent Intel
chipsets because those have only EHCI controllers and handle high-speed
devices with a built-in hub.

All this is completely unrelated with a hardware bug in the first
revision of these Intel chipsets, which made USB audio just break.

Regards,
Clemens
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Messages in current thread:
[LAU] No duplex mode with the EHCI driver and USB hub. Is th..., Pablo Fernández, (Mon Nov 7, 9:53 pm)
Re: [LAU] No duplex mode with the EHCI driver and USB hub. I..., Clemens Ladisch, (Wed Nov 9, 11:39 am)