Re: [PATCH v6.2 1/1] Input: Add userio module

From: Lyude
Date: Mon Oct 26 2015 - 09:52:09 EST


Hi! So, I'm guessing you want me to merge this with the patch I've got
right now and post the new version? (Just making sure since I'm a bit
new to this :)

On Sat, 2015-10-24 at 15:40 -0700, Dmitry Torokhov wrote:
> Hi Stephen,
>
> On Fri, Oct 23, 2015 at 04:47:46PM -0400, cpaul@xxxxxxxxxx wrote:
> > From: Stephen Chandler Paul <cpaul@xxxxxxxxxx>
> >
> > Debugging input devices, specifically laptop touchpads, can be
> > tricky
> > without having the physical device handy. Here we try to remedy
> > that
> > with userio. This module allows an application to connect to a
> > character
> > device provided by the kernel, and emulate any serio device. In
> > combination with userspace programs that can record PS/2 devices
> > and
> > replay them through the /dev/userio device, this allows developers
> > to
> > debug driver issues on the PS/2 level with devices simply by
> > requesting
> > a recording from the user experiencing the issue without having to
> > have
> > the physical hardware in front of them.
> >
> > Signed-off-by: Stephen Chandler Paul <cpaul@xxxxxxxxxx>
> > Reviewed-by: David Herrmann <dh.herrmann@xxxxxxxxx>
> > ---
> > Changes
> > * Remove the if (!userio) { return -1; } check that somehow got
> > left in.
> >
> > Sorry this took so long! I was wondering why you hadn't replied
> > yet, only to
> > notice I only made this change on my own tree and never sent out a
> > response
> > patch. Oops.
>
> Thank you for making all the changes.
>
> > +
> > +static ssize_t userio_char_read(struct file *file, char __user
> > *user_buffer,
> > + size_t count, loff_t *ppos)
> > +{
> > + struct userio_device *userio = file->private_data;
> > + int ret;
> > + size_t nonwrap_len, copylen;
> > + unsigned char buf[USERIO_BUFSIZE];
> > + unsigned long flags;
> > +
> > + if (!count)
> > + return 0;
>
> This is not quite right: read of size 0 should still check if there
> is
> data in the buffer and return -EAGAIN for non-blocking descriptors.
>
> I cooked a patch (below) that should adjust the read behavior (_+ a
> coupe of formatting changes), please take a look.
>
> Thanks!
>
--
Cheers,
Lyude

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/