Re: [PATCH v3] synaptics: Add min/max quirk for ThinkPad T431s, L440, L540, S1 Yoga and X1

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Apr 17, 2014 at 05:53:10PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 04/17/2014 05:35 PM, Dmitry Torokhov wrote:
> > Hi Hans,
> > 
> > On Thu, Apr 17, 2014 at 01:41:43PM +0200, Hans de Goede wrote:
> >> We expect that all the Haswell series will need such quirks, sigh.
> > 
> > Given this statement do we really want this to be handled in kernel?
> 
> I know this answer won't make you happy, but short term: Yes, we are
> getting many many bugreports about this, ie:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1060885
> https://bugzilla.redhat.com/show_bug.cgi?id=1068716
> https://bugzilla.redhat.com/show_bug.cgi?id=1085582
> https://bugzilla.redhat.com/show_bug.cgi?id=1085697
> https://bugzilla.redhat.com/show_bug.cgi?id=1086227
> 
> And by extending the *already present* quirk table we can get this
> issue resolved quickly, and also resolve it for people running
> older kernels through the various stable series.
> 
> > Maybe we simply want udev to fix up the limits with EVIOSABS(),
> 
> Ah, I did not know that it is possible to fixup the min/max values
> from user space, that is good to know.
> 
> > similarly to how we adjust keymaps for laptops?
> 
> We're currently looking into various ways to make this less painful,
> specifically for most laptops the problem seems to be the min value
> and not the max value. And the troublesome min value is the synaptics
> driver default, not the one we get from the firmware. The problem is
> we never ask the firmware because even though it has the "I can report
> min values" capability bit, its "maximum understood request" number
> is too low, so one of our 2 checks for getting the min value is
> failing. If we remove that check some models do give us a proper
> range (but not all, ie the T440s is still wrong).
> 
> We're currently trying to figure out if it will be safe for all models
> to remove the "maximum understood request" number check. That should ie
> remove the quirk for the x240 and possible others.
> 
> An other option to make this better is to switch the quirks to using
> pnp-ids, ie the L440 and L540 share the same pnp-id. Once you've
> merged the firmware_id patches I can take a shot at simplifying the
> quirk table that way. Downside is that we then probably need to
> put the firmware_id patches in the various stable kernels.
> 
> Note that even if we end up moving this to userspace, then we still
> need the firmware_id, because I believe any userspace solution should
> be using pnp-ids too.
> 
> TL;DR: It is complicated and for now we would like to continue with
> the quirks as we've done sofar. We are aware that this is undesirable
> from a maintenance pov and are looking into making this better.

OK, fair enough. I applied the patch.

Thanks.

-- 
Dmitry