From 86ef3f78b8bae808f41f74c506762ac345fdf893 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 14 Jun 2012 09:43:11 -0300 Subject: [media] radio-si470x: Don't unnecesarily read registers on G_TUNER Reading registers from the pcear USB dongles with the si470x causes a loud pop (and an alsa buffer overrun). Since most radio apps periodically call G_TUNER to update mono/stereo, signal and afc status this leads to the music . pop . music . pop . music -> not good. On the internet there is an howto for flashing the pcear with a newer firmware from the silabs reference boardto fix this, but: 1) This howto relies on a special version of the driver which allows firmware flashing 2) We should try to avoid the answer to a bug report being upgrade your firmware, if at all possible 3) Windows does not suffer from the pop sounds After a quick look at the driver I found at that the register reads are not necessary at all, as the device gives us the necessary status through usb interrupt packets, and the driver already uses these! Signed-off-by: Hans de Goede Signed-off-by: Mauro Carvalho Chehab --- drivers/media/radio/si470x/radio-si470x-common.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'drivers/media/radio/si470x/radio-si470x-common.c') diff --git a/drivers/media/radio/si470x/radio-si470x-common.c b/drivers/media/radio/si470x/radio-si470x-common.c index d485b79222fd..5dbb897e14de 100644 --- a/drivers/media/radio/si470x/radio-si470x-common.c +++ b/drivers/media/radio/si470x/radio-si470x-common.c @@ -583,14 +583,16 @@ static int si470x_vidioc_g_tuner(struct file *file, void *priv, struct v4l2_tuner *tuner) { struct si470x_device *radio = video_drvdata(file); - int retval; + int retval = 0; if (tuner->index != 0) return -EINVAL; - retval = si470x_get_register(radio, STATUSRSSI); - if (retval < 0) - return retval; + if (!radio->status_rssi_auto_update) { + retval = si470x_get_register(radio, STATUSRSSI); + if (retval < 0) + return retval; + } /* driver constants */ strcpy(tuner->name, "FM"); -- cgit v1.2.3-59-g8ed1b