From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Oleksandr Andrushchenko <andr2000@gmail.com>
Cc: xen-devel@lists.xenproject.org, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org, jgross@suse.com, lyan@suse.com,
boris.ostrovsky@oracle.com, konrad.wilk@oracle.com,
andrii_chepurnyi@epam.com,
Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Subject: Re: [PATCH v3 2/2] Input: xen-kbdfront - allow better run-time configuration
Date: Wed, 16 May 2018 14:08:17 -0700 [thread overview]
Message-ID: <20180516210817.GF21971@dtor-ws> (raw)
In-Reply-To: <e9882c52-3641-7c32-1f64-dd9c4f35de5f@gmail.com>
On Wed, May 16, 2018 at 08:47:30PM +0300, Oleksandr Andrushchenko wrote:
> On 05/16/2018 08:15 PM, Dmitry Torokhov wrote:
> > Hi Oleksandr,
> >
> > On Mon, May 14, 2018 at 05:40:29PM +0300, Oleksandr Andrushchenko wrote:
> > > @@ -211,93 +220,114 @@ static int xenkbd_probe(struct xenbus_device *dev,
> > > if (!info->page)
> > > goto error_nomem;
> > > - /* Set input abs params to match backend screen res */
> > > - abs = xenbus_read_unsigned(dev->otherend,
> > > - XENKBD_FIELD_FEAT_ABS_POINTER, 0);
> > > - ptr_size[KPARAM_X] = xenbus_read_unsigned(dev->otherend,
> > > - XENKBD_FIELD_WIDTH,
> > > - ptr_size[KPARAM_X]);
> > > - ptr_size[KPARAM_Y] = xenbus_read_unsigned(dev->otherend,
> > > - XENKBD_FIELD_HEIGHT,
> > > - ptr_size[KPARAM_Y]);
> > > - if (abs) {
> > > - ret = xenbus_write(XBT_NIL, dev->nodename,
> > > - XENKBD_FIELD_REQ_ABS_POINTER, "1");
> > > - if (ret) {
> > > - pr_warn("xenkbd: can't request abs-pointer\n");
> > > - abs = 0;
> > > - }
> > > - }
> > > + /*
> > > + * The below are reverse logic, e.g. if the feature is set, then
> > > + * do not expose the corresponding virtual device.
> > > + */
> > > + with_kbd = !xenbus_read_unsigned(dev->nodename,
> > > + XENKBD_FIELD_FEAT_DSBL_KEYBRD, 0);
> > > - touch = xenbus_read_unsigned(dev->nodename,
> > > - XENKBD_FIELD_FEAT_MTOUCH, 0);
> > > - if (touch) {
> > > + with_ptr = !xenbus_read_unsigned(dev->nodename,
> > > + XENKBD_FIELD_FEAT_DSBL_POINTER, 0);
> > > +
> > > + /* Direct logic: if set, then create multi-touch device. */
> > > + with_mtouch = xenbus_read_unsigned(dev->nodename,
> > > + XENKBD_FIELD_FEAT_MTOUCH, 0);
> > > + if (with_mtouch) {
> > > ret = xenbus_write(XBT_NIL, dev->nodename,
> > > XENKBD_FIELD_REQ_MTOUCH, "1");
> > > if (ret) {
> > > pr_warn("xenkbd: can't request multi-touch");
> > > - touch = 0;
> > > + with_mtouch = 0;
> > > }
> > > }
> > Does it make sense to still end up calling xenkbd_connect_backend() when
> > all interfaces (keyboard, pointer, and multitouch) are disabled? Should
> > we do:
> >
> > if (!(with_kbd || || with_ptr || with_mtouch))
> > return -ENXIO;
> >
> > ?
> It does make sense. Then we probably need to move all xenbus_read_unsigned
> calls to the very beginning of the .probe, so no memory allocations are made
> which will be useless if we return -ENXIO, e.g. something like
>
> static int xenkbd_probe(struct xenbus_device *dev,
> const struct xenbus_device_id *id)
> {
> int ret, i;
> bool with_mtouch, with_kbd, with_ptr;
> struct xenkbd_info *info;
> struct input_dev *kbd, *ptr, *mtouch;
>
> <read with_mtouch, with_kbd, with_ptr here>
>
> if (!(with_kbd | with_ptr | with_mtouch))
> return -ENXIO;
>
> Does the above looks ok?
Yes. Another option is to keep the check where I suggested and do
if (...) {
ret = -ENXIO;
goto error;
}
Whichever you prefer is fine with me.
Thanks.
--
Dmitry
next prev parent reply other threads:[~2018-05-16 21:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 14:40 [PATCH v3 1/2] xen/kbdif: Sync up with the canonical definition in Xen Oleksandr Andrushchenko
2018-05-14 14:40 ` [PATCH v3 2/2] Input: xen-kbdfront - allow better run-time configuration Oleksandr Andrushchenko
2018-05-16 17:15 ` Dmitry Torokhov
2018-05-16 17:47 ` Oleksandr Andrushchenko
2018-05-16 21:08 ` Dmitry Torokhov [this message]
2018-05-17 5:31 ` Oleksandr Andrushchenko
2018-05-17 13:08 ` Boris Ostrovsky
2018-05-17 13:09 ` Oleksandr Andrushchenko
2018-05-17 14:29 ` Konrad Rzeszutek Wilk
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180516210817.GF21971@dtor-ws \
--to=dmitry.torokhov@gmail.com \
--cc=andr2000@gmail.com \
--cc=andrii_chepurnyi@epam.com \
--cc=boris.ostrovsky@oracle.com \
--cc=jgross@suse.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lyan@suse.com \
--cc=oleksandr_andrushchenko@epam.com \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).