On Sun, Jun 25, 2023 at 10:30 AM Bastien Nocera hadess@hadess.net wrote:
On Fri, 2023-06-23 at 10:37 +0200, Benjamin Tissoires wrote:
On Jun 21 2023, Greg KH wrote:
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
Extract the internal code inside a helper function, fix the initialization of the parameters used in the helper function (`hidpp->answer_available` was not reset and `*response` wasn't too), and use a `do {...} while();` loop.
Fixes: 586e8fede795 ("HID: logitech-hidpp: Retry commands when device is busy") Cc: stable@vger.kernel.org Signed-off-by: Benjamin Tissoires benjamin.tissoires@redhat.com
as requested by https://lore.kernel.org/all/CAHk-=wiMbF38KCNhPFiargenpSBoecSXTLQACKS2UMyo_Vu... This is a rewrite of that particular piece of code.
drivers/hid/hid-logitech-hidpp.c | 102 +++++++++++++++++++++++--
1 file changed, 61 insertions(+), 41 deletions(-)
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid- logitech-hidpp.c index dfe8e09a18de..3d1ffe199f08 100644 --- a/drivers/hid/hid-logitech-hidpp.c +++ b/drivers/hid/hid-logitech-hidpp.c @@ -275,21 +275,20 @@ static int __hidpp_send_report(struct hid_device *hdev, }
/*
- hidpp_send_message_sync() returns 0 in case of success, and
something else
- in case of a failure.
- If ' something else' is positive, that means that an error
has been raised
- by the protocol itself.
- If ' something else' is negative, that means that we had a
classic error
- (-ENOMEM, -EPIPE, etc...)
- Effectively send the message to the device, waiting for its
answer.
- Must be called with hidpp->send_mutex locked
- Same return protocol than hidpp_send_message_sync():
- success on 0
- negative error means transport error
*/
- positive value means protocol error
-static int hidpp_send_message_sync(struct hidpp_device *hidpp, +static int __do_hidpp_send_message_sync(struct hidpp_device *hidpp, struct hidpp_report *message, struct hidpp_report *response)
__must_hold(&hidpp->send_mutex) ?
Good point. I'll add this in v2.
I'm still waiting for some feedback from the people who particpated in the original BZ, but the new bug is harder to reproduce. Anyway, there is no rush IMO.
The problem is only ever going to show up in very limited circumstances after the logic fix was applied.
You need a hardware problem (such as the controller being too busy to answer) to trigger the problems fixed by this patch. I don't see a way to reliably reproduce it unless you inject that hardware error.
Some people on the Bz were able to reproduce with multiple reboots. But it's not as urgent as previously, and we were close to the 6.4 final when I sent it. I'll make sure this goes into 6.5 and gets proper stable backports FWIW.
Cheers, Benjamin