From 86ef3f78b8bae808f41f74c506762ac345fdf893 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 14 Jun 2012 09:43:11 -0300 Subject: [PATCH] [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 ++++++---- drivers/media/radio/si470x/radio-si470x-usb.c | 12 +++++++++--- drivers/media/radio/si470x/radio-si470x.h | 1 + 3 files changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/media/radio/si470x/radio-si470x-common.c b/drivers/media/radio/si470x/radio-si470x-common.c index d485b79..5dbb897 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"); diff --git a/drivers/media/radio/si470x/radio-si470x-usb.c b/drivers/media/radio/si470x/radio-si470x-usb.c index f412f7a..0da5c98 100644 --- a/drivers/media/radio/si470x/radio-si470x-usb.c +++ b/drivers/media/radio/si470x/radio-si470x-usb.c @@ -399,12 +399,16 @@ static void si470x_int_in_callback(struct urb *urb) } } - if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0) + /* Sometimes the device returns len 0 packets */ + if (urb->actual_length != RDS_REPORT_SIZE) goto resubmit; - if (urb->actual_length > 0) { + radio->registers[STATUSRSSI] = + get_unaligned_be16(&radio->int_in_buffer[1]); + + if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS)) { /* Update RDS registers with URB data */ - for (regnr = 0; regnr < RDS_REGISTER_NUM; regnr++) + for (regnr = 1; regnr < RDS_REGISTER_NUM; regnr++) radio->registers[STATUSRSSI + regnr] = get_unaligned_be16(&radio->int_in_buffer[ regnr * RADIO_REGISTER_SIZE + 1]); @@ -480,6 +484,7 @@ resubmit: radio->int_in_running = 0; } } + radio->status_rssi_auto_update = radio->int_in_running; } @@ -560,6 +565,7 @@ static int si470x_start_usb(struct si470x_device *radio) "submitting int urb failed (%d)\n", retval); radio->int_in_running = 0; } + radio->status_rssi_auto_update = radio->int_in_running; return retval; } diff --git a/drivers/media/radio/si470x/radio-si470x.h b/drivers/media/radio/si470x/radio-si470x.h index 4921cab..2a0a46f 100644 --- a/drivers/media/radio/si470x/radio-si470x.h +++ b/drivers/media/radio/si470x/radio-si470x.h @@ -161,6 +161,7 @@ struct si470x_device { struct completion completion; bool stci_enabled; /* Seek/Tune Complete Interrupt */ + bool status_rssi_auto_update; /* Does RSSI get updated automatic? */ #if defined(CONFIG_USB_SI470X) || defined(CONFIG_USB_SI470X_MODULE) /* reference to USB and video device */ -- 2.7.4