Re: [PATCH] usbcore: fix BABBLE failed enumeration of legacy USB2devices on USB3 bus

From: Greg Kroah-Hartman
Date: Tue Jan 07 2014 - 19:32:22 EST

On Tue, Dec 24, 2013 at 04:19:18AM +0000, Marius Silaghi wrote:
> From: Marius C Silaghi <msilaghi@xxxxxxx>
> This patch is generated against the last kernel version in the github kernel repository.

We work off of the trees, not github :)

> Some older families of USB2 cameras (STC-XXXXXUSB) do not support querying only the first 8 bytes of their
> device descriptor and therefore fail at enumeration on USB3 HCDs, with babble error -75 as they send more than
> the expected 8 bytes. The proposed patch extends the mechanism used for non USB3 HCDs in the first part of
> the same function, and successively tries to query both the 8 byte prefix of the device descriptor, as well as
> the whole device descriptor (in case the old style query of the 8 byte prefix fails).
> In fact, for the cameras I try to fix, the preferred condition is the negation of the one in the proposed patch,
> "if (!USE_NEW_SCHEME(retry_counter))", to try first the version successful on this case, but I keep the
> current order of the "if" branches to ensure clean continuation of support for other supported devices.
> Signed-off-by: Marius C Silaghi <msilaghi@xxxxxxx>

I'll let Sarah take this patch, if it passes her testing.


greg k-h
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