[PATCH 1/2] media/rc/imon.c: make send_packet() delay larger for 15c2:0036

[Kevin Baradon]

Imon device 15c2:0036 need a higher delay between send_packet() calls.
Also use interruptible wait to avoid load average going too high (and let caller handle signals).

Signed-off-by: Kevin Baradon <kevin.baradon@xxxxxxxxx>
---
 drivers/media/rc/imon.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index dec203b..178b946 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -112,6 +112,7 @@ struct imon_context {
 	bool tx_control;
 	unsigned char usb_rx_buf[8];
 	unsigned char usb_tx_buf[8];
+	unsigned int send_packet_delay;
 
 	struct tx_t {
 		unsigned char data_buf[35];	/* user data buffer */
@@ -185,6 +186,10 @@ enum {
 	IMON_KEY_PANEL	= 2,
 };
 
+enum {
+	IMON_NEED_20MS_PKT_DELAY = 1
+};
+
 /*
  * USB Device ID for iMON USB Control Boards
  *
@@ -215,7 +220,7 @@ static struct usb_device_id imon_usb_id_table[] = {
 	/* SoundGraph iMON OEM Touch LCD (IR & 4.3" VGA LCD) */
 	{ USB_DEVICE(0x15c2, 0x0035) },
 	/* SoundGraph iMON OEM VFD (IR & VFD) */
-	{ USB_DEVICE(0x15c2, 0x0036) },
+	{ USB_DEVICE(0x15c2, 0x0036), .driver_info = IMON_NEED_20MS_PKT_DELAY },
 	/* device specifics unknown */
 	{ USB_DEVICE(0x15c2, 0x0037) },
 	/* SoundGraph iMON OEM LCD (IR & LCD) */
@@ -535,12 +540,12 @@ static int send_packet(struct imon_context *ictx)
 	kfree(control_req);
 
 	/*
-	 * Induce a mandatory 5ms delay before returning, as otherwise,
+	 * Induce a mandatory delay before returning, as otherwise,
 	 * send_packet can get called so rapidly as to overwhelm the device,
 	 * particularly on faster systems and/or those with quirky usb.
 	 */
-	timeout = msecs_to_jiffies(5);
-	set_current_state(TASK_UNINTERRUPTIBLE);
+	timeout = msecs_to_jiffies(ictx->send_packet_delay);
+	set_current_state(TASK_INTERRUPTIBLE);
 	schedule_timeout(timeout);
 
 	return retval;
@@ -2335,6 +2340,10 @@ static int imon_probe(struct usb_interface *interface,
 
 	}
 
+	/* default send_packet delay is 5ms but some devices need more */
+	ictx->send_packet_delay = id->driver_info & IMON_NEED_20MS_PKT_DELAY ?
+				  20 : 5;
+
 	usb_set_intfdata(interface, ictx);
 
 	if (ifnum == 0) {
-- 
1.7.10.4


> >  /*
> >   * In certain use cases, mouse mode isn't really helpful, and could actually
> >   * cause confusion, so allow disabling it when the IR device is open.
> > @@ -535,12 +540,15 @@ static int send_packet(struct imon_context *ictx)
> >  	kfree(control_req);
> >  
> >  	/*
> > -	 * Induce a mandatory 5ms delay before returning, as otherwise,
> > +	 * Induce a mandatory delay before returning, as otherwise,
> >  	 * send_packet can get called so rapidly as to overwhelm the device,
> >  	 * particularly on faster systems and/or those with quirky usb.
> > +	 * Do not use TASK_UNINTERRUPTIBLE as this routine is called quite often
> > +	 * and doing so will increase load average slightly. Caller will handle
> > +	 * signals itself.
> >  	 */
> > -	timeout = msecs_to_jiffies(5);
> > -	set_current_state(TASK_UNINTERRUPTIBLE);
> > +	timeout = msecs_to_jiffies(send_packet_delay);
> > +	set_current_state(TASK_INTERRUPTIBLE);
> >  	schedule_timeout(timeout);
> >  
> >  	return retval;
> 
> Regards,
> Mauro

Regards,
Kevin

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