Re: [PATCH] HID: magicmouse: ignore 'ivalid report id' while switching modes

On 08/18/2011 09:36 AM, Jaikumar Ganesh wrote:

Hi Chase

On Thu, Aug 18, 2011 at 9:25 AM, Chase Douglas
<chase.douglas@canonical.com <mailto:chase.douglas@canonical.com>> wrote:

    On 08/17/2011 12:59 PM, Jaikumar Ganesh wrote:
    > From: Jiri Kosina <jkosina@suse.cz <mailto:jkosina@suse.cz>>
    >
    > 23746a introduced this commit but was reverted in c3a492.
    > The trackpad uses report Ids which are not present in the
    > report descriptor. These reports ids are not documented
    > anywhere. There are devices in the market (Apple magic tracpkad,
    > BT version 2.0 is one such device) with the same device id,
    > which fail when we use 0xd7 as the report id. So we need the EIO
    > change of 23746a as a failsafe to work with these devices.
    >
    > Original Author: Jiri Kosina <jkosina@suse.cz
    <mailto:jkosina@suse.cz>>
    >
    > Signed-off-by: Jaikumar Ganesh <jaikumarg@android.com
    <mailto:jaikumarg@android.com>>

    I worry this may just be papering over a bug elsewhere in the system
    again. I'm going to try to git bisect this today.

 
The original commit explains in detail why it used to work before, so
its not a regression in that sense. The commit was present in 2.6.39
stable tree too but was reverted in 3.0 tree. 

It was reverted because it was papering over a bug in the bluetooth
stack, and when that bug was fixed this commit broke things again.

I've determined that there's a bug between Ubuntu's 3.0-1.2 and 3.0-2.3
kernels. There does not appear to be any Ubuntu specific patches that
went in between those versions that would affect this, but there was a
rebase from upstream 3.0-rc3 to 3.0-rc4. There is likely a bug
introduced sometime in there.

I'll be digging deeper...

-- Chase