kernel/linux.git/drivers/usb/host/ehci-timer.c, branch v6.19.12

usb: host: Replace empty define with do while

2018-09-28T13:03:37+00:00

It's dangerous to use empty code define. Furthermore it lead to the following warning: "suggest braces around empty body in an « else » statement" So let's replace emptyness by "do {} while(0)" Furthermore, as suggested by Joe Perches, rename the macro to INCR. Signed-off-by: Corentin Labbe Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: host: ehci: Remove redundant license text

2017-11-07T14:45:02+00:00

Now that the SPDX tag is in all USB files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: add SPDX identifiers to all remaining files in drivers/usb/

2017-11-04T10:48:02+00:00

It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/usb/ and include/linux/usb* files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner Cc: Kate Stewart Cc: Philippe Ombredanne Signed-off-by: Greg Kroah-Hartman Acked-by: Felipe Balbi Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

usb: Make use of ktime_* comparison functions

2017-06-03T09:08:04+00:00

Start using ktime_* compare functions to make the code backportable. Now that may be a bit tricky due to recent change of ktime_t. Signed-off-by: Mariusz Skamra Acked-by: Kuppuswamy Sathyanarayanan Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

ktime: Cleanup ktime_set() usage

2016-12-25T16:21:22+00:00

ktime_set(S,N) was required for the timespec storage type and is still useful for situations where a Seconds and Nanoseconds part of a time value needs to be converted. For anything where the Seconds argument is 0, this is pointless and can be replaced with a simple assignment. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra

ktime: Get rid of the union

2016-12-25T16:21:22+00:00

ktime is a union because the initial implementation stored the time in scalar nanoseconds on 64 bit machine and in a endianess optimized timespec variant for 32bit machines. The Y2038 cleanup removed the timespec variant and switched everything to scalar nanoseconds. The union remained, but become completely pointless. Get rid of the union and just keep ktime_t as simple typedef of type s64. The conversion was done with coccinelle and some manual mopping up. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra

USB: EHCI: add a delay when unlinking an active QH

2016-02-03T21:14:52+00:00

Michael Reutman reports that an AMD/ATI EHCI host controller on one of his computers does not stop transferring data when an active bulk QH is unlinked from the async schedule. Apparently that host controller fails to implement the IAA mechanism correctly when an active QH is unlinked. This leads to data corruption, because the controller continues to update the QH in memory when the driver doesn't expect it. As a result, the next URB submitted for that QH can hang, because the link pointers for the TD queue have been messed up. This misbehavior is observed quite regularly. To be fair, the EHCI spec (section 4.8.2) says that active QHs should not be unlinked. It goes on to recommend a procedure that involves waiting for the QH to go inactive before unlinking it. In the real world this is impractical, not least because the QH may _never_ go inactive. (What were they thinking?) Sometimes we have no choice but to unlink an active QH. In an attempt to avoid the problems that can ensue, this patch changes how the driver decides when the unlink is complete. In addition to waiting through two IAA cycles, in cases where the QH was not known to be inactive beforehand we now wait until a 2-ms period has elapsed with the host controller making no change to the QH data structure (the hw_current and hw_token fields in particular). The intuition here is that after such a long period, the endpoint must be NAKing and hopefully the QH has been dropped from the host controller's internal cache. There's no way to know if this reasoning is really valid -- the spec is no help in this regard -- but at least this approach fixes Michael's problem. The test for whether the QH is already known to be inactive involves the reason for unlinking the QH originally. If it was unlinked because it had halted, or it stopped in response to a short read, or it overlaid a dummy TD (a silicon bug), then it certainly is inactive. If it was unlinked because the TD queue was empty and no TDs have been added to the queue in the meantime, then it must be inactive. Or if the hardware status indicates that the QH is currently halted (even if that wasn't the reason for unlinking it), then it is inactive. Otherwise, if none of those checks apply, we go through the 2-ms delay. Signed-off-by: Alan Stern Reported-by: Michael Reutman Tested-by: Michael Reutman Signed-off-by: Greg Kroah-Hartman

USB: EHCI: improve handling of the ehci->iaa_in_progress flag

2016-02-03T21:14:52+00:00

This patch improves the way ehci-hcd handles the iaa_in_progress flag. The current code is somewhat careless in this regard: The flag is meaningless when the root hub isn't running, most particularly after the root hub has been suspended. But in start_iaa_cycle(), the driver checks the flag before checking the root hub's state. They should be checked in the opposite order. That routine also sets the flag too early, before it has definitely committed to starting an IAA cycle. The flag is turned off in end_unlink_async(). Upcoming changes will call that routine at other times, not just at the end of an IAA cycle. The two actions are logically separate (although related), so we separate out a new routine to be called in place of end_unlink_async() whenever an IAA cycle ends: end_iaa_cycle(). iaa_in_progress should be turned off when the root hub is suspended -- we certainly don't want it still to be set when the root hub resumes. Therefore the call to end_unlink_async() in ehci_bus_suspend() should also be replaced with a call to end_iaa_cycle(). Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: EHCI: store reason for unlinking a QH

2016-02-03T21:14:52+00:00

This patch replaces the "exception" bitflag in the ehci_qh structure with a more explicit "unlink_reason" bitmask. This is for use in the following patch, where we will need to have a good idea of the reason for unlinking a QH, not just "something exceptional happened". Signed-off-by: Alan Stern Tested-by: Michael Reutman Signed-off-by: Greg Kroah-Hartman

USB: EHCI: improve interrupt qh unlink

2013-08-12T18:43:48+00:00

ehci-hcd currently unlinks an interrupt QH when it becomes empty, that is, after its last URB completes. This works well because in almost all cases, the completion handler for an interrupt URB resubmits the URB; therefore the QH doesn't become empty and doesn't get unlinked. When we start using tasklets for URB completion, this scheme won't work as well. The resubmission won't occur until the tasklet runs, which will be some time after the completion is queued with the tasklet. During that delay, the QH will be empty and so will be unlinked unnecessarily. To prevent this problem, this patch adds a 5-ms time delay before empty interrupt QHs are unlinked. Most often, during that time the interrupt URB will be resubmitted and thus we can avoid unlinking the QH. Signed-off-by: Alan Stern Signed-off-by: Ming Lei Signed-off-by: Greg Kroah-Hartman