[Adding Mathias.] On Thu, Mar 06, 2014 at 12:27:59AM -0600, Robert Hancock wrote: > On 05/03/14 11:17 PM, Robert Hancock wrote: > >I have a USB 3.0 multi-card reader device: > > > >Bus 004 Device 002: ID 05e3:0743 Genesys Logic, Inc. > > > >which seems to work fine in 3.13.4 (Fedora version kernel-3.13.4-200 > >specifically) but fails in 3.13.5 (specifically kernel-3.13.5-202). > >Below is what I get in dmesg. Essentially there's a bunch of > >input/output errors making the reader mostly unusable. > > > >This is on an Intel Haswell machine with this controller: > > > >00:14.0 USB controller [0c03]: Intel Corporation 8 Series/C220 Series > >Chipset Family USB xHCI [8086:8c31] (rev 05) > > > >It looks like there were some XHCI commits that went into 3.13.5 so it > >seems likely one of those is the cause. I can try current git if there's > >anything in there that's likely to fix it. But it does seem like a > >regression got into the stable kernel in this respect. > > Bisecting between 3.13.4 and 3.13.5 gives me this: > > c8f44f98901994832ccecb87c3dd7900274b699a is the first bad commit > commit c8f44f98901994832ccecb87c3dd7900274b699a > Author: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> > Date: Fri Jan 31 11:26:25 2014 -0800 > > xhci 1.0: Limit arbitrarily-aligned scatter gather. Yes, this is a known regression. That commit should be reverted in 3.14-rc shortly, and the patch will be backported to stable kernels. Mathias is taking over as xHCI maintainer, and he will queue the revert patches to Greg shortly. Sarah Sharp > > commit 247bf557273dd775505fb9240d2d152f4f20d304 upstream. > > xHCI 1.0 hosts have a set of requirements on how to align transfer > buffers on the endpoint rings called "TD fragment" rules. When the > ax88179_178a driver added support for scatter gather in 3.12, with > commit 804fad45411b48233b48003e33a78f290d227c8 "USBNET: ax88179_178a: > enable tso if usb host supports sg dma", it broke the device under xHCI > 1.0 hosts. Under certain network loads, the device would see an > unexpected short packet from the host, which would cause the device to > stop sending ethernet packets, even through USB packets would still be > sent. > > Commit 35773dac5f86 "usb: xhci: Link TRB must not occur within a USB > payload burst" attempted to fix this. It was a quick hack to partially > implement the TD fragment rules. However, it caused regressions in the > usb-storage layer and userspace USB drivers using libusb. The patches > to attempt to fix this are too far reaching into the USB core, and we > really need to implement the TD fragment rules correctly in the xHCI > driver, instead of continuing to wallpaper over the issues. > > Disable arbitrarily-aligned scatter-gather in the xHCI driver for 1.0 > hosts. Only the ax88179_178a driver checks the no_sg_constraint flag, > so don't set it for 1.0 hosts. This should not impact usb-storage or > usbfs behavior, since they pass down max packet sized aligned sg-list > entries (512 for USB 2.0 and 1024 for USB 3.0). > > Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> > Tested-by: Mark Lord <mlord@xxxxxxxxx> > Cc: David Laight <David.Laight@xxxxxxxxxx> > Cc: Bjørn Mork <bjorn@xxxxxxx> > Cc: Freddy Xin <freddy@xxxxxxxxxxx> > Cc: Ming Lei <ming.lei@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
