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[media] media: rc: nuvoton: ignore spurious interrupt when logical device is being disabled

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When removing module nuvoton-cir I get a fifo overrun warning.
It turned out to be caused by a spurious interrupt when the logical CIR
device is being disabled (although no interrupt source bit being set).
Reading the interrupt status register returns 0xff, therefore the fifo
overrun bit is mistakenly interpreted as being set.

Fix this by ignoring interrupts when interrupt source and status register
reads return 0xff.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Heiner Kallweit 2016-07-31 10:42:55 -03:00 committed by Mauro Carvalho Chehab
parent 033919e0f8
commit d14f291b62
1 changed files with 9 additions and 0 deletions
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9
drivers/media/rc/nuvoton-cir.c
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@ -886,6 +886,15 @@ static irqreturn_t nvt_cir_isr(int irq, void *data)
status = nvt_cir_reg_read(nvt, CIR_IRSTS);
iren = nvt_cir_reg_read(nvt, CIR_IREN);
/* At least NCT6779D creates a spurious interrupt when the
* logical device is being disabled.
*/
if (status == 0xff && iren == 0xff) {
spin_unlock_irqrestore(&nvt->nvt_lock, flags);
nvt_dbg_verbose("Spurious interrupt detected");
return IRQ_HANDLED;
}
/* IRQ may be shared with CIR WAKE, therefore check for each
* status bit whether the related interrupt source is enabled
*/