[PATCH] V4L/DVB: cx88: Add module parameter to disable IR

[PATCH] V4L/DVB: cx88: Add module parameter to disable IR

[Jeremy Kerr]

From: Jeremy Kerr <jk@ozlabs.org>

Currently, the cx88-input code unconditionally establishes an input
device for IR events. On some cards, this sets up a hrtimer to poll the
IR status frequently - I get around 200 wakeups per second from this
polling, and don't use the IR ports.

Although the hrtimer is only run when the input device is opened, the
device is actually unconditionally opened by kbd_connect, because we
have the EV_KEY bit set in the input device descriptor. In effect, the
IR device is always opened (and so polling) if CONFIG_VT.

This change adds a module parameter, 'ir_disable' to disable the IR
code, and not register this input device at all. This drastically
reduces the number of wakeups per second for me.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

---
 drivers/media/video/cx88/cx88-input.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/media/video/cx88/cx88-input.c b/drivers/media/video/cx88/cx88-input.c
index fc777bc..d49af18 100644
--- a/drivers/media/video/cx88/cx88-input.c
+++ b/drivers/media/video/cx88/cx88-input.c
@@ -67,6 +67,10 @@ static int ir_debug;
 module_param(ir_debug, int, 0644);	/* debug level [IR] */
 MODULE_PARM_DESC(ir_debug, "enable debug messages [IR]");
 
+static int ir_disable;
+module_param(ir_disable, int, 0644);
+MODULE_PARM_DESC(ir_disable, "disable IR support");
+
 #define ir_dprintk(fmt, arg...)	if (ir_debug) \
 	printk(KERN_DEBUG "%s IR: " fmt , ir->core->name , ##arg)
 
@@ -244,6 +248,9 @@ int cx88_ir_init(struct cx88_core *core, struct pci_dev *pci)
 				 * used with a full-code IR table
 				 */
 
+	if (ir_disable)
+		return 0;
+
 	ir = kzalloc(sizeof(*ir), GFP_KERNEL);
 	input_dev = input_allocate_device();
 	if (!ir || !input_dev)

Re: [PATCH] V4L/DVB: cx88: Add module parameter to disable IR

[Mariusz Białończyk]

On 2010-11-18 07:43, Jeremy Kerr wrote:
> Currently, the cx88-input code unconditionally establishes an input
> device for IR events. On some cards, this sets up a hrtimer to poll the
> IR status frequently - I get around 200 wakeups per second from this
> polling, and don't use the IR ports.
>
> Although the hrtimer is only run when the input device is opened, the
> device is actually unconditionally opened by kbd_connect, because we
> have the EV_KEY bit set in the input device descriptor. In effect, the
> IR device is always opened (and so polling) if CONFIG_VT.
>
> This change adds a module parameter, 'ir_disable' to disable the IR
> code, and not register this input device at all. This drastically
> reduces the number of wakeups per second for me.

AFAIK we have disable support in cx88:
http://git.linuxtv.org/media_tree.git?a=commit;h=89c3bc78075042ae1f4452687f626acce06b3b21

isn't it related with your patch?

-- 
Mariusz Białończyk
jabber/e-mail: manio@skyboo.net
http://manio.skyboo.net

Re: [PATCH] V4L/DVB: cx88: Add module parameter to disable IR

[Jeremy Kerr]

Hi Mariusz,

> AFAIK we have disable support in cx88:
> http://git.linuxtv.org/media_tree.git?a=commit;h=89c3bc78075042ae1f4452687f
> 626acce06b3b21

Ah, my bad - I was working off Linus' tree, and looks like that patch hasn't 
hit mainline yet.

As an aside, that patch has a problem: the MODULE_PARAM_DESC line uses 
'latency', not 'disable_ir'.

Cheers,


Jeremy