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V4L/DVB (6952): Add code for autoloading em28xx-alsa, if needed 

Older em28xx devices does implement standard Audio Class.

However, on newer devices, this were replaced by a Vendor Class. This
patch autodetects that an em28xx lacks Audio Class and auto-loads
em28xx-alsa, for the devices that implements only a Vendor Class.

For devices with Audio Class, snd-usb-audio module will provide an ALSA
interface.

This patch uses the request_module_async function as defined on cx88-mpeg.c, 
originally wrote by Markus Rechberger.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Mauro Carvalho Chehab 2008-01-05 09:59:03 -03:00
parent 6d79468dd8
commit d7448a8d9d
3 changed files with 41 additions and 1 deletions
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1
drivers/media/video/em28xx/em28xx-audio.c
View File

@ -472,7 +472,6 @@ static struct em28xx_ops audio_ops = {
static int __init em28xx_alsa_register(void)
{
request_module("em28xx");
return em28xx_register_extension(&audio_ops);
}

38
drivers/media/video/em28xx/em28xx-video.c
View File

@ -1668,6 +1668,10 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
dev->em28xx_read_reg_req = em28xx_read_reg_req;
dev->is_em2800 = em28xx_boards[dev->model].is_em2800;
errCode = em28xx_read_reg(dev, CHIPID_REG);
if (errCode >= 0)
em28xx_info("em28xx chip ID = %d\n", errCode);
em28xx_pre_card_setup(dev);
errCode = em28xx_config(dev);
@ -1794,6 +1798,25 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
return 0;
}
#if defined(CONFIG_MODULES) && defined(MODULE)
static void request_module_async(struct work_struct *work)
{
struct em28xx *dev = container_of(work,
struct em28xx, request_module_wk);
if (!dev->has_audio_class)
request_module("em28xx-alsa");
}
static void request_modules(struct em28xx *dev)
{
INIT_WORK(&dev->request_module_wk, request_module_async);
schedule_work(&dev->request_module_wk);
}
#else
#define request_modules(dev)
#endif /* CONFIG_MODULES */
/*
* em28xx_usb_probe()
* checks for supported devices
@ -1864,6 +1887,18 @@ static int em28xx_usb_probe(struct usb_interface *interface,
dev->devno = nr;
dev->model = id->driver_info;
/* Checks if audio is provided by some interface */
for (i = 0; i < udev->config->desc.bNumInterfaces; i++) {
uif = udev->config->interface[i];
if (uif->altsetting[0].desc.bInterfaceClass == USB_CLASS_AUDIO) {
dev->has_audio_class = 1;
break;
}
}
printk(KERN_INFO DRIVER_NAME " %s usb audio class\n",
dev->has_audio_class ? "Has" : "Doesn't have");
/* compute alternate max packet sizes */
uif = udev->actconfig->interface[0];
@ -1900,6 +1935,9 @@ static int em28xx_usb_probe(struct usb_interface *interface,
/* save our data pointer in this interface device */
usb_set_intfdata(interface, dev);
request_modules(dev);
return 0;
}

3
drivers/media/video/em28xx/em28xx.h
View File

@ -246,6 +246,7 @@ struct em28xx {
unsigned int has_msp34xx:1;
unsigned int has_tda9887:1;
unsigned int stream_on:1; /* Locks streams */
unsigned int has_audio_class:1;
int video_inputs; /* number of video inputs */
struct list_head devlist;
@ -295,6 +296,8 @@ struct em28xx {
enum em28xx_stream_state stream;
enum em28xx_io_method io;
struct work_struct request_module_wk;
/* locks */
struct mutex lock;
spinlock_t queue_lock;