Messages in this thread | | | Date | Thu, 1 Dec 2011 14:19:48 +0800 | From | Feng Tang <> | Subject | Re: [PATCH 2/2] Input: tsc2007 - Add a z1_low_threshhold platform data parameter |
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On Thu, 1 Dec 2011 13:47:26 +0800 Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:
> On Wed, Nov 30, 2011 at 10:34:18AM +0800, Feng Tang wrote: > > On Tue, 29 Nov 2011 17:23:10 +0800 > > Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > > > > > On Tue, Nov 29, 2011 at 04:12:58PM +0800, Feng Tang wrote: > > > > This originates from a patch in Meego IVI kernel with the name > > > > linux-2.6.37-connext-0027-tsc2007.patch > > > > There is no author info excepte a line "From MeeGo > > > > <kernel@meego.com>" > > > > > > > > When integrating tsc2007 on Intel IVI platform, there are a lot > > > > of noise data whose z1 value is around 10 which is not a sane > > > > "z1". So add a "z1_low_threshhold" to filter those nosie data, > > > > to make the device work properly. > > > > > > Sounds like a task for userspace to ignore pressure that is too > > > low. Bonus points for making it configurable so user can adjust > > > sensitivity. > > > > Actually, there is one more point :), without this patch, the > > driver won't work on our platforms. > > > > The tsc2007_soft_irq will keep reading the input data unless there > > is no valid pressure data. In our case, those noise data will be > > seen as valid data during tsc2007_calculate_pressure(), and the > > tsc2007_soft_irq will run endlessly. > > Even if we add the pressure threshold would not that noise cause > endless stream of interrupts?
No, there is no endless interrupts for tsc2007. Without the z1 threshold, the while circle in tsc2007_soft_irq will run endlessly as the noise data will be seen as a valid data:
rt = tsc2007_calculate_pressure(ts, &tc); if (rt == 0 && !ts->get_pendown_state) { /* * If pressure reported is 0 and we don't have * callback to check pendown state, we have to * assume that pen was lifted up. */ break; }
With the z1 threshold check, the rt will be 0 for noise data, and the code flow broke out.
> > Also, what kind of z2 is reported with low z1? And do you implement > get_pendown_state()?
z2 seems normal as some data between 3000-4000. We don't have a get_pendown_state().
Thanks, Feng > > Thanks. >
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