]> git.baikalelectronics.ru Git - kernel.git/commit
Revert "xhci 1.0: Limit arbitrarily-aligned scatter gather."
authorMathias Nyman <mathias.nyman@linux.intel.com>
Fri, 7 Mar 2014 15:06:57 +0000 (17:06 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 7 Mar 2014 19:48:13 +0000 (11:48 -0800)
commit4fe14b9f1bc8676a9d61b2358c146b85531dd7d4
treef39f2ab4e1a24843cd95144344111f7ec52af2ee
parent17c0e431ad38ff8206aa861daa132c9178f6ce58
Revert "xhci 1.0: Limit arbitrarily-aligned scatter gather."

This reverts commit 12858b52864e40bc17a982d5a17878fc00e4c6d9.

This commit, together with commit 1d1ef311e7b8fed056d2b88f46fd7a926edf5a9c
"USBNET: ax88179_178a: enable tso if usb host supports sg dma" were
origially added to get xHCI 1.0 hosts and usb ethernet ax88179_178a devices
working together with scatter gather. xHCI 1.0 hosts pose some requirement on how transfer
buffers are aligned, setting this requirement for 1.0 hosts caused USB 3.0 mass
storage devices to fail more frequently.

USB 3.0 mass storage devices used to work before 3.14-rc1.  Theoretically,
the TD fragment rules could have caused an occasional disk glitch.
Now the devices *will* fail, instead of theoretically failing.
>From a user perspective, this looks like a regression; the USB device obviously
fails on 3.14-rc1, and may sometimes silently fail on prior kernels.

The proper soluition is to implement the TD fragment rules required, but for now
this patch needs to be reverted to get USB 3.0 mass storage devices working at the
level they used to.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/host/xhci.c