From: Jiri Kosina <jkosina@suse.cz>
To: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Cc: Henrik Rydberg <rydberg@euromail.se>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Stephane Chatty <chatty@enac.fr>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 3/5] hid: Parse the device before adding it
Date: Tue, 3 Apr 2012 06:06:36 -0700 (PDT) [thread overview]
Message-ID: <alpine.LNX.2.00.1204030603550.9041@pobox.suse.cz> (raw)
In-Reply-To: <CAN+gG=G9KSjSFmWpxpPLzMzz14ePAhQKTJZjQBsPeq2iztZ17A@mail.gmail.com>
On Tue, 3 Apr 2012, Benjamin Tissoires wrote:
> > The hid bus is populated by devices created by the usb and bluetooth
> > subsystems. The hid device is then broadcast to userland via uevents.
> > Currently, the parsing of the hid reports is done during probe of
> > the hid device, after the device has been broadcast. In order to
> > allow for the report descriptors to influence the device properties,
> > it is desirable to parse the device _before_ it is broadcast to
> > userland. In actuality, the parsing depends only accidentally on
> > the driver being present, so it can be trivially achieved.
> >
> > Something also needs to be done for the report_fixup handler, which
> > seems to be the only hard device-driver coupling in the code.
> >
> > Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
> > ---
> > drivers/hid/hid-core.c | 2 +-
> > drivers/hid/usbhid/hid-core.c | 5 +++++
> > 2 files changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> > index 35ba9d9..8a7b59e 100644
> > --- a/drivers/hid/hid-core.c
> > +++ b/drivers/hid/hid-core.c
> > @@ -658,7 +658,7 @@ int hid_parse_report(struct hid_device *device, __u8 *start,
> > hid_parser_reserved
> > };
> >
> > - if (device->driver->report_fixup)
> > + if (device->driver && device->driver->report_fixup)
> > start = device->driver->report_fixup(device, start, &size);
>
> Well, this is not a good solution for the following drivers:
> hid-zydacron
> hid-prodikeys
> hid-uclogic
> hid-samsung
> hid-sony, etc...
>
> they all use report_fixup and as the parse is made only once, they
> won't be able to work properly.
For completness -- please see a discussion that's a little bit related to
this (and namely the patch I have proposed yesterday) here:
http://www.spinics.net/lists/linux-input/msg20061.html
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2012-04-03 13:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-03 7:05 [RFC 0/5] hid: Extending the device-driver matching mechanism Henrik Rydberg
2012-04-03 7:05 ` [RFC 1/5] hid: Remove multitouch quirk Henrik Rydberg
2012-04-08 23:56 ` Jiri Kosina
2012-04-03 7:05 ` [RFC 2/5] hid-multitouch: Prepare driver for new device ids Henrik Rydberg
2012-04-03 7:05 ` [RFC 3/5] hid: Parse the device before adding it Henrik Rydberg
2012-04-03 8:41 ` Benjamin Tissoires
2012-04-03 13:06 ` Jiri Kosina [this message]
2012-04-03 7:05 ` [RFC 4/5] hid: Add idtags to modalias Henrik Rydberg
2012-04-03 8:45 ` Benjamin Tissoires
2012-04-03 10:57 ` Henrik Rydberg
2012-04-03 7:05 ` [RFC 5/5] hid: Remove multitouch devices from blacklist Henrik Rydberg
2012-04-03 8:46 ` Benjamin Tissoires
2012-04-03 8:38 ` [RFC 0/5] hid: Extending the device-driver matching mechanism Benjamin Tissoires
2012-04-03 10:55 ` Henrik Rydberg
2012-04-08 23:53 ` Jiri Kosina
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