diff options
| author | Matt Reimer <mreimer@vpop.net> | 2006-06-08 22:46:48 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2006-06-08 22:46:48 +0100 |
| commit | e2f04e18941dbd3826901540a0be03f1728f8822 (patch) | |
| tree | 1a52bcac2d2f165089d7784025659f21e6db57b0 | |
| parent | 0c27c5d5b93339df4def7ced77ea5be26df4d84b (diff) | |
| download | linux-e2f04e18941dbd3826901540a0be03f1728f8822.tar.bz2 | |
[ARM] 3546/1: PATCH: subtle lost interrupts bug on i.MX
Patch from Matt Reimer
There is a subtle bug in the GPIO interrupt status register
handling in arch/arm/mach-imx/irq.c:imx_gpio_ack_irq(). The
documentation states that a 1 should be written to the relevant bit to
acknowledge a GPIO interrupt, but that is not what the code does.
The problem is that the |= writes back 1s for all the *other*
interrupts represented in the register, so interrupts could get lost.
For example, if interrupts are pending for GPIO B10 and B12, ISR_B
would have the value 0x00001400. Then when the interrupt code handles
GPIO B10, it eventually calls imx_gpio_ack_irq(IRQ_GPIOB(10)), which
effectively does this:
ISR_B |= 1 << 10;
with the result that (0x00001400 | 0x00000400) is written, clearing
the interrupt status bits for *both* GPIO B10 and B12.
The fix is to write 1s only for the interrupts we want to clear.
The same problem seems to be occurring in the DMA code; this patch
does not address those issues.
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| -rw-r--r-- | arch/arm/mach-imx/irq.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/mach-imx/irq.c b/arch/arm/mach-imx/irq.c index eeb8a6d4a399..a5de5f1da9f2 100644 --- a/arch/arm/mach-imx/irq.c +++ b/arch/arm/mach-imx/irq.c @@ -127,7 +127,7 @@ static void imx_gpio_ack_irq(unsigned int irq) { DEBUG_IRQ("%s: irq %d\n", __FUNCTION__, irq); - ISR(IRQ_TO_REG(irq)) |= 1 << ((irq - IRQ_GPIOA(0)) % 32); + ISR(IRQ_TO_REG(irq)) = 1 << ((irq - IRQ_GPIOA(0)) % 32); } static void |