> On Fri, Aug 14, 2015 at 03:40:18PM -0500, Michael Welling wrote:
> > On Fri, Aug 14, 2015 at 11:43:52AM -0700, Greg
> Wilson-Lindberg wrote:
> > > Thank you very much,
> > > Regards, Greg
> > >
> >
> > To replicate the issue I did the following:
> >
> > - Started a touchscreen enabled application ts_test
> >
> > - In another terminal started a dump of /dev/iio:device0 hexdump -C
> > /dev/iio\:device0
> >
> > - In yet another terminal enable the buffer cd
> > /sys/bus/iio/devices/iio\:device0 echo 1 >
> > scan_elements/in_voltage4_en echo 1 > buffer/enable
> >
> > Once the buffer is enabled the hexdump window starts spewing out
> > readings as expected. The touchscreen is unresponsive as expected.
> >
> > Then I started occassionally enabling and disabling the buffer and
> > noticed something very off. When enabling the buffer sometimes the
> > readings from the hexdump would start and abruptly stop. In
> this state
> > the entire system is nonresponsive. None of the terminals are
> > excepting input and the system is in complete deadlock.
> Then I touched
> > the screen and the deadlock is lifted and readings started again.
> >
> > As if the behavior was not weird enough, occassionally after the
> > buffer is disabled, the touchscreen readings are mangled.
> >
> > Next step, figure out what is going wrong.
> >
>
> It seems the drivers are being flooded with IRQENB_EOS
> interrupts causing the lockup.
>
> By adding the following to the tiadc_irq_h function the lockup stops.
>
> .
> .
> if (status & IRQENB_EOS) {
> tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_EOS);
> return IRQ_HANDLED;
> }
> .
> .
>
> Now the IRQENB_EOS is also handled in the touchscreen driver
> so this is may not be an appropriate fix but at least it
> fixes the lockup.
>
> Try adding the snippet above to ti_am335x_adc.c and see if it
> makes your program stop locking up.
>
> Then we need to find a solution that makes the maintainers happy.
>
>
I've applied this to the ti_am335x_adc.c driver in both the 3.14.49-ti-r62 & 3.14.49-ti-r73 kernels from RCN and they both suffered touch screen lockups over night.
Here is what I did:
static irqreturn_t tiadc_irq_h(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct tiadc_device *adc_dev = iio_priv(indio_dev);
unsigned int status, config;
status = tiadc_readl(adc_dev, REG_IRQSTATUS);
/*
* ADC and touchscreen share the IRQ line.
* FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
*/
if (status & IRQENB_FIFO1OVRRUN) {
/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
config = tiadc_readl(adc_dev, REG_CTRL);
config &= ~(CNTRLREG_TSCSSENB);
tiadc_writel(adc_dev, REG_CTRL, config);
tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
| IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
return IRQ_HANDLED;
} else if (status & IRQENB_FIFO1THRES) {
/* Disable irq and wake worker thread */
tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
return IRQ_WAKE_THREAD;
}
if (status & IRQENB_EOS) {
tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_EOS);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
Regards,
Greg--
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