[PATCH] [staging] lirc_serial: allocate irq at init time

[PATCH] [staging] lirc_serial: allocate irq at init time

[Jarod Wilson]

There's really no good reason not to just grab the desired IRQ at driver
init time, instead of every time the lirc device node is accessed. This
also improves the speed and reliability with which a serial transmitter
can operate, as back-to-back transmission attempts (i.e., channel change
to a multi-digit channel) don't have to spend time acquiring and then
releasing the IRQ for every digit, sometimes multiple times, if lircd
has been told to use the min_repeat parameter.

CC: devel@driverdev.osuosl.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
---
 drivers/staging/lirc/lirc_serial.c |   44 +++++++++++++++++------------------
 1 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/lirc/lirc_serial.c b/drivers/staging/lirc/lirc_serial.c
index 1c3099b..805df91 100644
--- a/drivers/staging/lirc/lirc_serial.c
+++ b/drivers/staging/lirc/lirc_serial.c
@@ -838,7 +838,23 @@ static int hardware_init_port(void)
 
 static int init_port(void)
 {
-	int i, nlow, nhigh;
+	int i, nlow, nhigh, result;
+
+	result = request_irq(irq, irq_handler,
+			     IRQF_DISABLED | (share_irq ? IRQF_SHARED : 0),
+			     LIRC_DRIVER_NAME, (void *)&hardware);
+
+	switch (result) {
+	case -EBUSY:
+		printk(KERN_ERR LIRC_DRIVER_NAME ": IRQ %d busy\n", irq);
+		return -EBUSY;
+	case -EINVAL:
+		printk(KERN_ERR LIRC_DRIVER_NAME
+		       ": Bad irq number or handler\n");
+		return -EINVAL;
+	default:
+		break;
+	};
 
 	/* Reserve io region. */
 	/*
@@ -893,34 +909,17 @@ static int init_port(void)
 		printk(KERN_INFO LIRC_DRIVER_NAME  ": Manually using active "
 		       "%s receiver\n", sense ? "low" : "high");
 
+	dprintk("Interrupt %d, port %04x obtained\n", irq, io);
 	return 0;
 }
 
 static int set_use_inc(void *data)
 {
-	int result;
 	unsigned long flags;
 
 	/* initialize timestamp */
 	do_gettimeofday(&lasttv);
 
-	result = request_irq(irq, irq_handler,
-			     IRQF_DISABLED | (share_irq ? IRQF_SHARED : 0),
-			     LIRC_DRIVER_NAME, (void *)&hardware);
-
-	switch (result) {
-	case -EBUSY:
-		printk(KERN_ERR LIRC_DRIVER_NAME ": IRQ %d busy\n", irq);
-		return -EBUSY;
-	case -EINVAL:
-		printk(KERN_ERR LIRC_DRIVER_NAME
-		       ": Bad irq number or handler\n");
-		return -EINVAL;
-	default:
-		dprintk("Interrupt %d, port %04x obtained\n", irq, io);
-		break;
-	};
-
 	spin_lock_irqsave(&hardware[type].lock, flags);
 
 	/* Set DLAB 0. */
@@ -945,10 +944,6 @@ static void set_use_dec(void *data)
 	soutp(UART_IER, sinp(UART_IER) &
 	      (~(UART_IER_MSI|UART_IER_RLSI|UART_IER_THRI|UART_IER_RDI)));
 	spin_unlock_irqrestore(&hardware[type].lock, flags);
-
-	free_irq(irq, (void *)&hardware);
-
-	dprintk("freed IRQ %d\n", irq);
 }
 
 static ssize_t lirc_write(struct file *file, const char *buf,
@@ -1256,6 +1251,9 @@ exit_serial_exit:
 static void __exit lirc_serial_exit_module(void)
 {
 	lirc_serial_exit();
+
+	free_irq(irq, (void *)&hardware);
+
 	if (iommap != 0)
 		release_mem_region(iommap, 8 << ioshift);
 	else
-- 
1.7.1

Re: [PATCH] [staging] lirc_serial: allocate irq at init time

[Greg KH]

On Thu, Jun 16, 2011 at 03:31:46PM -0400, Jarod Wilson wrote:
> There's really no good reason not to just grab the desired IRQ at driver
> init time, instead of every time the lirc device node is accessed. This
> also improves the speed and reliability with which a serial transmitter
> can operate, as back-to-back transmission attempts (i.e., channel change
> to a multi-digit channel) don't have to spend time acquiring and then
> releasing the IRQ for every digit, sometimes multiple times, if lircd
> has been told to use the min_repeat parameter.
> 
> CC: devel@driverdev.osuosl.org
> Signed-off-by: Jarod Wilson <jarod@redhat.com>
> ---
>  drivers/staging/lirc/lirc_serial.c |   44 +++++++++++++++++------------------
>  1 files changed, 21 insertions(+), 23 deletions(-)

This patch doesn't apply to the staging-next branch, care to respin it
and resend it so I can apply it?

thanks,

greg k-h

Re: [PATCH] [staging] lirc_serial: allocate irq at init time

[Jarod Wilson]

On Tue, Jul 5, 2011 at 1:21 PM, Greg KH <greg@kroah.com> wrote:
> On Thu, Jun 16, 2011 at 03:31:46PM -0400, Jarod Wilson wrote:
>> There's really no good reason not to just grab the desired IRQ at driver
>> init time, instead of every time the lirc device node is accessed. This
>> also improves the speed and reliability with which a serial transmitter
>> can operate, as back-to-back transmission attempts (i.e., channel change
>> to a multi-digit channel) don't have to spend time acquiring and then
>> releasing the IRQ for every digit, sometimes multiple times, if lircd
>> has been told to use the min_repeat parameter.
>>
>> CC: devel@driverdev.osuosl.org
>> Signed-off-by: Jarod Wilson <jarod@redhat.com>
>> ---
>>  drivers/staging/lirc/lirc_serial.c |   44 +++++++++++++++++------------------
>>  1 files changed, 21 insertions(+), 23 deletions(-)
>
> This patch doesn't apply to the staging-next branch, care to respin it
> and resend it so I can apply it?

This actually got merged into mainline a few days ago via the media tree.

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=c4b0afee3c1730cf9b0f6ad21729928d23d3918e

Do you want me to take a look at what's in staging-next and fix that
up to apply on top of the above?

-- 
Jarod Wilson
jarod@wilsonet.com

Re: [PATCH] [staging] lirc_serial: allocate irq at init time

[Greg KH]

On Thu, Jul 07, 2011 at 08:31:28PM -0400, Jarod Wilson wrote:
> On Tue, Jul 5, 2011 at 1:21 PM, Greg KH <greg@kroah.com> wrote:
> > On Thu, Jun 16, 2011 at 03:31:46PM -0400, Jarod Wilson wrote:
> >> There's really no good reason not to just grab the desired IRQ at driver
> >> init time, instead of every time the lirc device node is accessed. This
> >> also improves the speed and reliability with which a serial transmitter
> >> can operate, as back-to-back transmission attempts (i.e., channel change
> >> to a multi-digit channel) don't have to spend time acquiring and then
> >> releasing the IRQ for every digit, sometimes multiple times, if lircd
> >> has been told to use the min_repeat parameter.
> >>
> >> CC: devel@driverdev.osuosl.org
> >> Signed-off-by: Jarod Wilson <jarod@redhat.com>
> >> ---
> >>  drivers/staging/lirc/lirc_serial.c |   44 +++++++++++++++++------------------
> >>  1 files changed, 21 insertions(+), 23 deletions(-)
> >
> > This patch doesn't apply to the staging-next branch, care to respin it
> > and resend it so I can apply it?
> 
> This actually got merged into mainline a few days ago via the media tree.
> 
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=c4b0afee3c1730cf9b0f6ad21729928d23d3918e
> 
> Do you want me to take a look at what's in staging-next and fix that
> up to apply on top of the above?

No, if it went in there, that's fine with me.

greg k-h