On Tue, Jun 24, 2014 at 05:14:42PM +0300, Mathias Nyman wrote: > From: Julius Werner <jwerner@xxxxxxxxxxxx> > > The current XHCI driver recalculates the Context Entries field in the > Slot Context on every add_endpoint() and drop_endpoint() call. In the > case of drop_endpoint(), it seems to assume that the add_flags will > always contain every endpoint for the new configuration, which is not > necessarily correct if you don't make assumptions about how the USB core > uses the add_endpoint/drop_endpoint interface (add_flags only contains > endpoints that are new additions in the new configuration). > > Furthermore, EP0_FLAG is not consistently set in add_flags throughout > the lifetime of a device. This means that when all endpoints are > dropped, the Context Entries field can be set to 0 (which is invalid and > may cause a Parameter Error) or -1 (which is interpreted as 31 and > causes the driver to keep using the old, incorrect value). > > The only surefire way to set this field right is to also take all > existing endpoints into account, and to force the value to 1 (meaning > only EP0 is active) if no other endpoint is found. This patch implements > that as a single step in the final check_bandwidth() call and removes > the intermediary calculations from add_endpoint() and drop_endpoint(). > > Signed-off-by: Julius Werner <jwerner@xxxxxxxxxxxx> > Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> > --- > drivers/usb/host/xhci.c | 51 +++++++++++++++++-------------------------------- > 1 file changed, 18 insertions(+), 33 deletions(-) Is this something for older (i.e. stable) kernels? thanks, greg k-h -- 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
