Messages in this thread Patch in this message | | | Subject | Re: [PATCH] I2C fixes for 2.6.10-rc2 | Date | Tue, 30 Nov 2004 16:13:39 -0800 | From | Greg KH <> |
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ChangeSet 1.2223.2.5, 2004/11/24 14:25:49-08:00, aris@cathedrallabs.org
[PATCH] i2c-elektor: get rid of cli/sti
this patch get rid of cli()/sti(). while correcting this I found that when a process wakes by an interrupt, pcf_pending doesn't come back to 0 and next caller will return imediately. also, there are other drivers with the exact same problem. if you don't have any comments on this, I'll do the same for other drivers.
[I2C] i2c-elektor: getting rid of cli()/sti() usage
Signed-off-by: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
drivers/i2c/busses/i2c-elektor.c | 22 ++++++++++++++++++---- 1 files changed, 18 insertions(+), 4 deletions(-)
diff -Nru a/drivers/i2c/busses/i2c-elektor.c b/drivers/i2c/busses/i2c-elektor.c --- a/drivers/i2c/busses/i2c-elektor.c 2004-11-30 16:01:05 -08:00 +++ b/drivers/i2c/busses/i2c-elektor.c 2004-11-30 16:01:05 -08:00 @@ -59,6 +59,7 @@ static wait_queue_head_t pcf_wait; static int pcf_pending; +static spinlock_t lock; /* ----- local functions ---------------------------------------------- */ @@ -111,14 +112,24 @@ static void pcf_isa_waitforpin(void) { int timeout = 2; + long flags; if (irq > 0) { - cli(); + spin_lock_irqsave(&lock, flags); if (pcf_pending == 0) { - interruptible_sleep_on_timeout(&pcf_wait, timeout*HZ ); - } else + spin_unlock_irqrestore(&lock, flags); + if (interruptible_sleep_on_timeout(&pcf_wait, + timeout*HZ)) { + spin_lock_irqsave(&lock, flags); + if (pcf_pending == 1) { + pcf_pending = 0; + } + spin_unlock_irqrestore(&lock, flags); + } + } else { pcf_pending = 0; - sti(); + spin_unlock_irqrestore(&lock, flags); + } } else { udelay(100); } @@ -126,7 +137,9 @@ static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id, struct pt_regs *regs) { + spin_lock(&lock); pcf_pending = 1; + spin_unlock(&lock); wake_up_interruptible(&pcf_wait); return IRQ_HANDLED; } @@ -134,6 +147,7 @@ static int pcf_isa_init(void) { + spin_lock_init(&lock); if (!mmapped) { if (!request_region(base, 2, "i2c (isa bus adapter)")) { printk(KERN_ERR - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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