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Commit dd89601d authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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V4L/DVB (9133): v4l: disconnect kernel number from minor 



The v4l core creates four different video devices (video, vbi, radio, vtx)
and each has its own range of minor numbers. However, modern devices keep
increasing the number of devices that they need so a maximum of 64 video
devices will not be enough in the future. In addition this scheme makes
it very hard to add new device types.

This patch disconnects the kernel number allocation (e.g. video0, video1,
etc.) from the actual minor number (just pick the first free minor).

This allows for much more flexibility in the future. However, it does
require the use of udev. For those who cannot use udev a new CONFIG option
was created that changes the allocation scheme back to the old behavior.

Thanks to Greg KH for suggesting this approach during the 2008 LPC.

In addition, several bugs were fixed in the ivtv and cx18 drivers: these
drivers try to allocate specific kernel numbers but that scheme contained
a bug which caused what should have been e.g. video17 to appear as e.g.
video2.

Signed-off-by: default avatarHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent e86a93dc

drivers/media/video/Kconfig

+9 −0
Original line number Original line Diff line number Diff line
@@ -72,6 +72,15 @@ config VIDEO_ADV_DEBUG 
	  V4L devices.

	  V4L devices.

	  In doubt, say N.

	  In doubt, say N.





config VIDEO_FIXED_MINOR_RANGES

	bool "Enable old-style fixed minor ranges for video devices"

	default n

	---help---

	  Say Y here to enable the old-style fixed-range minor assignments.

	  Only useful if you rely on the old behavior and use mknod instead of udev.



	  When in doubt, say N.



config VIDEO_HELPER_CHIPS_AUTO

config VIDEO_HELPER_CHIPS_AUTO

	bool "Autoselect pertinent encoders/decoders and other helper chips"

	bool "Autoselect pertinent encoders/decoders and other helper chips"

	default y

	default y

drivers/media/video/cx18/cx18-driver.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -175,7 +175,7 @@ MODULE_PARM_DESC(enc_pcm_buffers, 
		 "Encoder PCM buffers (in MB)\n"

		 "Encoder PCM buffers (in MB)\n"

		 "\t\t\tDefault: " __stringify(CX18_DEFAULT_ENC_PCM_BUFFERS));

		 "\t\t\tDefault: " __stringify(CX18_DEFAULT_ENC_PCM_BUFFERS));





MODULE_PARM_DESC(cx18_first_minor, "Set minor assigned to first card");

MODULE_PARM_DESC(cx18_first_minor, "Set kernel number assigned to first card");





MODULE_AUTHOR("Hans Verkuil");

MODULE_AUTHOR("Hans Verkuil");

MODULE_DESCRIPTION("CX23418 driver");

MODULE_DESCRIPTION("CX23418 driver");
@@ -959,7 +959,7 @@ static int module_start(void) 




	/* Validate parameters */

	/* Validate parameters */

	if (cx18_first_minor < 0 || cx18_first_minor >= CX18_MAX_CARDS) {

	if (cx18_first_minor < 0 || cx18_first_minor >= CX18_MAX_CARDS) {

		printk(KERN_ERR "cx18:  Exiting, ivtv_first_minor must be between 0 and %d\n",

		printk(KERN_ERR "cx18:  Exiting, cx18_first_minor must be between 0 and %d\n",

		     CX18_MAX_CARDS - 1);

		     CX18_MAX_CARDS - 1);

		return -1;

		return -1;

	}

	}

drivers/media/video/cx18/cx18-streams.c

+22 −19
Original line number Original line Diff line number Diff line
@@ -57,7 +57,7 @@ static struct file_operations cx18_v4l2_enc_fops = { 
static struct {

static struct {

	const char *name;

	const char *name;

	int vfl_type;

	int vfl_type;

	int minor_offset;

	int num_offset;

	int dma;

	int dma;

	enum v4l2_buf_type buf_type;

	enum v4l2_buf_type buf_type;

	struct file_operations *fops;

	struct file_operations *fops;
@@ -144,8 +144,8 @@ static int cx18_prep_dev(struct cx18 *cx, int type) 
{

{

	struct cx18_stream *s = &cx->streams[type];

	struct cx18_stream *s = &cx->streams[type];

	u32 cap = cx->v4l2_cap;

	u32 cap = cx->v4l2_cap;

	int minor_offset = cx18_stream_info[type].minor_offset;

	int num_offset = cx18_stream_info[type].num_offset;

	int minor;

	int num = cx->num + cx18_first_minor + num_offset;





	/* These four fields are always initialized. If v4l2dev == NULL, then

	/* These four fields are always initialized. If v4l2dev == NULL, then

	   this stream is not in use. In that case no other fields but these

	   this stream is not in use. In that case no other fields but these
@@ -164,9 +164,6 @@ static int cx18_prep_dev(struct cx18 *cx, int type) 
	    !(cap & (V4L2_CAP_VBI_CAPTURE | V4L2_CAP_SLICED_VBI_CAPTURE)))

	    !(cap & (V4L2_CAP_VBI_CAPTURE | V4L2_CAP_SLICED_VBI_CAPTURE)))

		return 0;

		return 0;





	/* card number + user defined offset + device offset */

	minor = cx->num + cx18_first_minor + minor_offset;



	/* User explicitly selected 0 buffers for these streams, so don't

	/* User explicitly selected 0 buffers for these streams, so don't

	   create them. */

	   create them. */

	if (cx18_stream_info[type].dma != PCI_DMA_NONE &&

	if (cx18_stream_info[type].dma != PCI_DMA_NONE &&
@@ -177,7 +174,7 @@ static int cx18_prep_dev(struct cx18 *cx, int type) 




	cx18_stream_init(cx, type);

	cx18_stream_init(cx, type);





	if (minor_offset == -1)

	if (num_offset == -1)

		return 0;

		return 0;





	/* allocate and initialize the v4l2 video device structure */

	/* allocate and initialize the v4l2 video device structure */
@@ -191,7 +188,7 @@ static int cx18_prep_dev(struct cx18 *cx, int type) 
	snprintf(s->v4l2dev->name, sizeof(s->v4l2dev->name), "cx18-%d",

	snprintf(s->v4l2dev->name, sizeof(s->v4l2dev->name), "cx18-%d",

			cx->num);

			cx->num);





	s->v4l2dev->minor = minor;

	s->v4l2dev->num = num;

	s->v4l2dev->parent = &cx->dev->dev;

	s->v4l2dev->parent = &cx->dev->dev;

	s->v4l2dev->fops = cx18_stream_info[type].fops;

	s->v4l2dev->fops = cx18_stream_info[type].fops;

	s->v4l2dev->release = video_device_release;

	s->v4l2dev->release = video_device_release;
@@ -227,7 +224,7 @@ static int cx18_reg_dev(struct cx18 *cx, int type) 
{

{

	struct cx18_stream *s = &cx->streams[type];

	struct cx18_stream *s = &cx->streams[type];

	int vfl_type = cx18_stream_info[type].vfl_type;

	int vfl_type = cx18_stream_info[type].vfl_type;

	int minor;

	int num;





	/* TODO: Shouldn't this be a VFL_TYPE_TRANSPORT or something?

	/* TODO: Shouldn't this be a VFL_TYPE_TRANSPORT or something?

	 * We need a VFL_TYPE_TS defined.

	 * We need a VFL_TYPE_TS defined.
@@ -245,38 +242,44 @@ static int cx18_reg_dev(struct cx18 *cx, int type) 
	if (s->v4l2dev == NULL)

	if (s->v4l2dev == NULL)

		return 0;

		return 0;





	minor = s->v4l2dev->minor;

	num = s->v4l2dev->num;

	/* card number + user defined offset + device offset */

	if (type != CX18_ENC_STREAM_TYPE_MPG) {

		struct cx18_stream *s_mpg = &cx->streams[CX18_ENC_STREAM_TYPE_MPG];



		if (s_mpg->v4l2dev)

			num = s_mpg->v4l2dev->num + cx18_stream_info[type].num_offset;

	}





	/* Register device. First try the desired minor, then any free one. */

	/* Register device. First try the desired minor, then any free one. */

	if (video_register_device(s->v4l2dev, vfl_type, minor) &&

	if (video_register_device(s->v4l2dev, vfl_type, num)) {

			video_register_device(s->v4l2dev, vfl_type, -1)) {

		CX18_ERR("Couldn't register v4l2 device for %s kernel number %d\n",

		CX18_ERR("Couldn't register v4l2 device for %s minor %d\n",

			s->name, num);

			s->name, minor);

		video_device_release(s->v4l2dev);

		video_device_release(s->v4l2dev);

		s->v4l2dev = NULL;

		s->v4l2dev = NULL;

		return -ENOMEM;

		return -ENOMEM;

	}

	}

	minor = s->v4l2dev->minor;

	num = s->v4l2dev->num;





	switch (vfl_type) {

	switch (vfl_type) {

	case VFL_TYPE_GRABBER:

	case VFL_TYPE_GRABBER:

		CX18_INFO("Registered device video%d for %s (%d MB)\n",

		CX18_INFO("Registered device video%d for %s (%d MB)\n",

			minor, s->name, cx->options.megabytes[type]);

			num, s->name, cx->options.megabytes[type]);

		break;

		break;





	case VFL_TYPE_RADIO:

	case VFL_TYPE_RADIO:

		CX18_INFO("Registered device radio%d for %s\n",

		CX18_INFO("Registered device radio%d for %s\n",

			minor - MINOR_VFL_TYPE_RADIO_MIN, s->name);

			num, s->name);

		break;

		break;





	case VFL_TYPE_VBI:

	case VFL_TYPE_VBI:

		if (cx->options.megabytes[type])

		if (cx->options.megabytes[type])

			CX18_INFO("Registered device vbi%d for %s (%d MB)\n",

			CX18_INFO("Registered device vbi%d for %s (%d MB)\n",

				minor - MINOR_VFL_TYPE_VBI_MIN,

				num,

				s->name, cx->options.megabytes[type]);

				s->name, cx->options.megabytes[type]);

		else

		else

			CX18_INFO("Registered device vbi%d for %s\n",

			CX18_INFO("Registered device vbi%d for %s\n",

				minor - MINOR_VFL_TYPE_VBI_MIN, s->name);

				num, s->name);

		break;

		break;

	}

	}

drivers/media/video/em28xx/em28xx-video.c

+3 −5
Original line number Original line Diff line number Diff line
@@ -1600,8 +1600,7 @@ static void em28xx_release_resources(struct em28xx *dev) 
	/*FIXME: I2C IR should be disconnected */

	/*FIXME: I2C IR should be disconnected */





	em28xx_info("V4L2 devices /dev/video%d and /dev/vbi%d deregistered\n",

	em28xx_info("V4L2 devices /dev/video%d and /dev/vbi%d deregistered\n",

				dev->vdev->minor-MINOR_VFL_TYPE_GRABBER_MIN,

				dev->vdev->num, dev->vbi_dev->num);

				dev->vbi_dev->minor-MINOR_VFL_TYPE_VBI_MIN);

	list_del(&dev->devlist);

	list_del(&dev->devlist);

	if (dev->sbutton_input_dev)

	if (dev->sbutton_input_dev)

		em28xx_deregister_snapshot_button(dev);

		em28xx_deregister_snapshot_button(dev);
@@ -2073,8 +2072,7 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev, 
	video_mux(dev, 0);

	video_mux(dev, 0);





	em28xx_info("V4L2 device registered as /dev/video%d and /dev/vbi%d\n",

	em28xx_info("V4L2 device registered as /dev/video%d and /dev/vbi%d\n",

				dev->vdev->minor-MINOR_VFL_TYPE_GRABBER_MIN,

				dev->vdev->num, dev->vbi_dev->num);

				dev->vbi_dev->minor-MINOR_VFL_TYPE_VBI_MIN);





	mutex_lock(&em28xx_extension_devlist_lock);

	mutex_lock(&em28xx_extension_devlist_lock);

	if (!list_empty(&em28xx_extension_devlist)) {

	if (!list_empty(&em28xx_extension_devlist)) {
@@ -2274,7 +2272,7 @@ static void em28xx_usb_disconnect(struct usb_interface *interface) 
		em28xx_warn

		em28xx_warn

		    ("device /dev/video%d is open! Deregistration and memory "

		    ("device /dev/video%d is open! Deregistration and memory "

		     "deallocation are deferred on close.\n",

		     "deallocation are deferred on close.\n",

				dev->vdev->minor-MINOR_VFL_TYPE_GRABBER_MIN);

				dev->vdev->num);





		dev->state |= DEV_MISCONFIGURED;

		dev->state |= DEV_MISCONFIGURED;

		em28xx_uninit_isoc(dev);

		em28xx_uninit_isoc(dev);

drivers/media/video/ivtv/ivtv-driver.c

+3 −3
Original line number Original line Diff line number Diff line
@@ -61,14 +61,14 @@ 
#include "tuner-xc2028.h"

#include "tuner-xc2028.h"





/* var to keep track of the number of array elements in use */

/* var to keep track of the number of array elements in use */

int ivtv_cards_active = 0;

int ivtv_cards_active;





/* If you have already X v4l cards, then set this to X. This way

/* If you have already X v4l cards, then set this to X. This way

   the device numbers stay matched. Example: you have a WinTV card

   the device numbers stay matched. Example: you have a WinTV card

   without radio and a PVR-350 with. Normally this would give a

   without radio and a PVR-350 with. Normally this would give a

   video1 device together with a radio0 device for the PVR. By

   video1 device together with a radio0 device for the PVR. By

   setting this to 1 you ensure that radio0 is now also radio1. */

   setting this to 1 you ensure that radio0 is now also radio1. */

int ivtv_first_minor = 0;

int ivtv_first_minor;





/* Master variable for all ivtv info */

/* Master variable for all ivtv info */

struct ivtv *ivtv_cards[IVTV_MAX_CARDS];

struct ivtv *ivtv_cards[IVTV_MAX_CARDS];
@@ -251,7 +251,7 @@ MODULE_PARM_DESC(newi2c, 
		 "\t\t\t-1 is autodetect, 0 is off, 1 is on\n"

		 "\t\t\t-1 is autodetect, 0 is off, 1 is on\n"

		 "\t\t\tDefault is autodetect");

		 "\t\t\tDefault is autodetect");





MODULE_PARM_DESC(ivtv_first_minor, "Set minor assigned to first card");

MODULE_PARM_DESC(ivtv_first_minor, "Set kernel number assigned to first card");





MODULE_AUTHOR("Kevin Thayer, Chris Kennedy, Hans Verkuil");

MODULE_AUTHOR("Kevin Thayer, Chris Kennedy, Hans Verkuil");

MODULE_DESCRIPTION("CX23415/CX23416 driver");

MODULE_DESCRIPTION("CX23415/CX23416 driver");