From: Jiri Kosina <jikos@kernel.org>
To: Johannes Hirte <johannes.hirte@datenkhaos.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
groeck@chromium.org, Nicolas Boichat <drinkcat@chromium.org>,
linux-usb@vger.kernel.org, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] HID: usbhid: do not sleep when opening device
Date: Tue, 18 Aug 2020 19:52:19 +0200 (CEST) [thread overview]
Message-ID: <nycvar.YFH.7.76.2008181951490.27422@cbobk.fhfr.pm> (raw)
In-Reply-To: <20200818115906.GA26874@latitude>
On Tue, 18 Aug 2020, Johannes Hirte wrote:
> > usbhid tries to give the device 50 milliseconds to drain its queues when
> > opening the device, but dies it naively by simply sleeping in open handler,
> > which slows down device probing (and thus may affect overall boot time).
> >
> > However we do not need to sleep as we can instead mark a point of time in
> > the future when we should start processing the events.
> >
> > Reported-by: Nicolas Boichat <drinkcat@chromium.org>
> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > ---
> >
>
> This change breaks various Logitech devices:
> https://bugzilla.kernel.org/show_bug.cgi?id=208935
Copy/pasting from the other thread:
=====
Yeah, this problem popped out also in other contexts, where many Logitech
devices didn't probe properly, because of the race where the first IRQ is
dropped on the floor (after hid_device_io_start() happens, but before the
50ms timeout passess), and report descriptor never gets parsed and
populated.
As this is just a boot time micro-optimization, I am going to revert the
patch for 5.9 now, and we can try to fix this properly for next merge
window.
=====
Thanks,
--
Jiri Kosina
SUSE Labs
prev parent reply other threads:[~2020-08-18 17:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 4:38 [PATCH v2] HID: usbhid: do not sleep when opening device Dmitry Torokhov
2020-06-10 5:28 ` Guenter Roeck
2020-06-16 15:14 ` Jiri Kosina
2020-08-18 11:59 ` Johannes Hirte
2020-08-18 17:52 ` Jiri Kosina [this message]
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