Hi, On Thursday 13 November 2014 05:53 PM, Vignesh R wrote: > Hi, > > On Wednesday 12 November 2014 06:30 PM, Johannes Pointner wrote: >> Hello Vignesh, >> >> I tried your patch version 3 on a customized board and had some >> behavior I couldn't explain. >> If I only use the touchscreen it works fine but if I also read values >> from the ADCs then I get a lot of pen_up events even if I am still >> touching the screen. >> For the test I read via >> # cat /sys/bus/iio/devices/iio\:device0/in_voltage5_raw >> values from the ADC in an busy loop as you explained in an email >> before. Did you also experience such behavior or do you know what >> causes it? > > Thanks for testing. I was able to fix this issue. Will post version 4 > shortly. > Were you able to test the v4 patch series on your board? Is the issue fixed? > Regards > Vignesh > >> >> Without the patches the touchscreen works fine during the iio test. >> >> Thanks, >> Hannes >> >> 2014-11-06 8:42 GMT+01:00 Vignesh R <vigneshr@xxxxxx>: >>> >>> >>> On Monday 03 November 2014 11:39 PM, Richard Cochran wrote: >>>> On Mon, Oct 27, 2014 at 04:38:27PM +0530, Vignesh R wrote: >>>>> This series of patches fix TSC defects related to lag in touchscreen >>>>> performance and cursor jump at touch release. The lag was result of >>>>> udelay in TSC interrupt handler. Cursor jump due to false pen-up event. >>>>> The patches implement Advisory 1.0.31 in silicon errata of am335x-evm >>>>> to avoid false pen-up events and remove udelay. >>>> >>>> That advisory has two workarounds. You have chosen the second one? >>> >>> Work around one. Hence 5 wire design is not broken. >>> >>>> >>>> The text of the second workaround says it only works on 4 wire setups, >>>> so I wonder how 5 wire designs will be affected. >>>> >>>>> The advisory says to use >>>>> steps 1 to 4 for ADC and 5 to 16 for TSC (assuming 4 wire TSC and 4 channel >>>>> ADC). >>>> >>>> No, it doesn't say that. (sprz360f.pdf) >>> >>> The pen up event detection happens immediately after charge step. Hence, >>> interchanging ADC and TSC steps makes sure that sampling of touch >>> co-ordinates and pen events are done one after the other. This >>> workaround was suggested by internal hardware folks. Earlier ADC steps >>> intervened between sampling of co-ordinates and pen event detection >>> which is not desirable. >>> >>>> >>>>> Further the X co-ordinate must be the last one to be sampled just >>>>> before charge step. The first two patches implement the required changes. >>>> >>>> FWIW, I implemented the first workaround and removed the udelay not >>>> too long ago. Like Sebastian, I saw the TSC unit hang after about >>>> 50000 interrupts when running with the workaround. >>>> >>>> Did you test you patch for very long? >>> >>> Yes, I tested for about 200000 interrupts and I didn't see any hang. >>> This patch series does not just implement workaround but also does some >>> minor changes, such as interchanging ADC and TSC steps etc, which makes >>> TSC driver more robust. Let me know if you encounter any issues with my >>> patch series. >>> >>> Regards >>> Vignesh >>> >>>> >>>> Thanks, >>>> Richard >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
