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staging/easycap: Improve interface to the videodev module
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The changes here represent an intermediate step towards bringing the
driver within the V4L2 framework.

Signed-off-by: Mike Thomas <rmthomas@sciolus.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Mike Thomas authored and Greg Kroah-Hartman committed Nov 10, 2010
1 parent ae59dad commit 268dfed
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93 changes: 64 additions & 29 deletions drivers/staging/easycap/README
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,9 @@ Two kinds of EasyCAP have this USB ID, namely:
BUILD OPTIONS AND DEPENDENCIES
------------------------------

Unless EASYCAP_DEBUG is defined during compilation it will not be possible
to select a debug level at the time of module installation.

If the parameter EASYCAP_IS_VIDEODEV_CLIENT is undefined during compilation
the built module is entirely independent of the videodev module, and when
the EasyCAP is physically plugged into a USB port the special files
Expand All @@ -33,41 +36,54 @@ respectively.
If the parameter EASYCAP_IS_VIDEODEV_CLIENT is defined during compilation
the built easycap module is configured to register with the videodev module,
in which case the special files created when the EasyCAP is plugged in are
/dev/video0 and /dev/easysnd0. Use of the easycap module as a client of
the videodev module has received very little testing as of June 2010.
/dev/video0 and /dev/easysnd0.

During in-tree builds the following should should be defined whenever the
parameter EASYCAP_IS_VIDEODEV_CLIENT is defined:

EASYCAP_NEEDS_V4L2_DEVICE_H
EASYCAP_NEEDS_V4L2_FOPS
EASYCAP_NEEDS_UNLOCKED_IOCTL

If the build is performed out-of-tree against older kernels the parameters
to be defined depend on the kernel version in a way which will not be
discussed here.


KNOWN BUILD PROBLEMS
KNOWN RUNTIME ISSUES
--------------------

(1) Recent gcc versions may generate the message:
(1) Intentionally, this driver will not stream material which is unambiguously
identified by the hardware as copy-protected. Normal video output will be
present for about a minute but will then freeze when this situation arises.

warning: the frame size of .... bytes is larger than 1024 bytes
(2) The controls for luminance, contrast, saturation, hue and volume may not
always work properly.

This warning can be suppressed by specifying in the Makefile:
(3) Reduced-resolution S-Video seems to suffer from moire artefacts.

EXTRA_CFLAGS += -Wframe-larger-than=8192

but it would be preferable to remove the cause of the warning.
INPUT NUMBERING
---------------

For the EasyCAP with S-VIDEO input cable the driver regards a request for
inputs numbered 0 or 1 as referring to CVBS and a request for input
numbered 5 as referring to S-VIDEO.

KNOWN RUNTIME ISSUES
--------------------
For the EasyCAP with four CVBS inputs the driver expects to be asked for
any one of inputs numbered 1,2,3,4. If input 0 is asked for, it is
interpreted as input 1.

(1) Randomly (maybe 5 to 10% of occasions) the driver fails to produce any
output at start-up. Closing mplayer (or whatever the user program is) and
restarting it restores normal performance without any other remedial action
being necessary. The reason for this is not known.

(2) Intentionally, this driver will not stream material which is unambiguously
identified by the hardware as copy-protected. The video output will freeze
within about a minute when this situation arises.
MODULE PARAMETERS
-----------------

(3) The controls for luminance, contrast, saturation, hue and volume may not
always work properly.
Three module parameters are defined:

(4) Reduced-resolution S-Video seems to suffer from moire artefacts. No
attempt has yet been made to rememdy this.
debug the easycap module is configured at diagnostic level n (0 to 9)
gain audio gain level n (0 to 31, default is 16)
bars 0 => testcard bars when incoming video signal is lost
1 => testcard bars when incoming video signal is lost (default)


SUPPORTED TV STANDARDS AND RESOLUTIONS
Expand All @@ -82,29 +98,37 @@ usable as (for example) the "norm=" parameter in the mplayer command:
PAL_60, NTSC_443,
PAL_M.

In addition, the driver offers "custom" pseudo-standards with a framerate
which is 20% of the usual framerate. These pseudo-standards are named:

PAL_BGHIN_SLOW, NTSC_N_443_SLOW,
PAL_Nc_SLOW, NTSC_N_SLOW,
SECAM_SLOW, NTSC_M_SLOW, NTSC_M_JP_SLOW,
PAL_60_SLOW, NTSC_443_SLOW,
PAL_M_SLOW.


The available picture sizes are:

at 25 frames per second: 720x576, 704x576, 640x480, 360x288, 320x240;
at 30 frames per second: 720x480, 640x480, 360x240, 320x240;
at 30 frames per second: 720x480, 640x480, 360x240, 320x240.


WHAT'S TESTED AND WHAT'S NOT
----------------------------

This driver is known to work with mplayer, mencoder, tvtime and sufficiently
recent versions of vlc. An interface to ffmpeg is implemented, but serious
audio-video synchronization problems remain.
This driver is known to work with mplayer, mencoder, tvtime, zoneminder,
xawtv, gstreamer and sufficiently recent versions of vlc. An interface
to ffmpeg is implemented, but serious audio-video synchronization problems
remain.

The driver is designed to support all the TV standards accepted by the
hardware, but as yet it has actually been tested on only a few of these.

I have been unable to test and calibrate the S-video input myself because I
do not possess any equipment with S-video output.

This driver does not understand the V4L1 IOCTL commands, so programs such
as camorama are not compatible. There are reports that the driver does
work with sufficiently recent (V4L2) versions of zoneminder, but I have not
attempted to confirm this myself.
This driver does not understand the V4L1 IOCTL commands.


UDEV RULES
Expand All @@ -120,6 +144,17 @@ ATTRS{idVendor}=="05e1", ATTRS{idProduct}=="0408", \
LABEL="easycap_rules_end"


MODPROBE CONFIGURATION
----------------------

The easycap module is in competition with the module snd-usb-audio for the
EasyCAP's audio channel, and its installation can be aided by providing a
file in directory /etc/modprobe.d with content:

options easycap gain=16 bars=1
install easycap /sbin/rmmod snd-usb-audio; /sbin/modprobe --ignore-install easycap


ACKNOWLEGEMENTS AND REFERENCES
------------------------------
This driver makes use of information contained in the Syntek Semicon DC-1125
Expand Down
16 changes: 3 additions & 13 deletions drivers/staging/easycap/easycap.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@
* EASYCAP_NEEDS_USBVIDEO_H
* EASYCAP_NEEDS_V4L2_DEVICE_H
* EASYCAP_NEEDS_V4L2_FOPS
* EASYCAP_NEEDS_UNLOCKED_IOCTL
*
* IF REQUIRED THEY MUST BE EXTERNALLY DEFINED, FOR EXAMPLE AS COMPILER
* OPTIONS.
Expand Down Expand Up @@ -81,25 +82,14 @@

/*vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv*/
#if defined(EASYCAP_IS_VIDEODEV_CLIENT)
#if (!defined(__OLD_VIDIOC_))
#define __OLD_VIDIOC_
#endif /* !defined(__OLD_VIDIOC_) */

#include <media/v4l2-dev.h>

#if defined(EASYCAP_NEEDS_V4L2_DEVICE_H)
#include <media/v4l2-device.h>
#endif /*EASYCAP_NEEDS_V4L2_DEVICE_H*/
#endif /*EASYCAP_IS_VIDEODEV_CLIENT*/
/*^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^*/

#if (!defined(__OLD_VIDIOC_))
#define __OLD_VIDIOC_
#endif /* !defined(__OLD_VIDIOC_) */
#include <linux/videodev2.h>

#include <linux/soundcard.h>

#if defined(EASYCAP_NEEDS_USBVIDEO_H)
#include <config/video/usbvideo.h>
#endif /*EASYCAP_NEEDS_USBVIDEO_H*/
Expand All @@ -110,7 +100,6 @@

#define STRINGIZE_AGAIN(x) #x
#define STRINGIZE(x) STRINGIZE_AGAIN(x)

/*---------------------------------------------------------------------------*/
/* VENDOR, PRODUCT: Syntek Semiconductor Co., Ltd
*
Expand Down Expand Up @@ -305,6 +294,8 @@ int hue_ok;
*/
/*---------------------------------------------------------------------------*/
struct easycap {
#define TELLTALE "expectedstring"
char telltale[16];
int isdongle;

/*vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv*/
Expand Down Expand Up @@ -501,7 +492,6 @@ long easycap_ioctl_noinode(struct file *, unsigned int, \
unsigned long);
int easycap_ioctl(struct inode *, struct file *, unsigned int, \
unsigned long);

/*vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv*/
#if defined(EASYCAP_IS_VIDEODEV_CLIENT)
int easycap_open_noinode(struct file *);
Expand Down
26 changes: 24 additions & 2 deletions drivers/staging/easycap/easycap_ioctl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -977,9 +977,13 @@ if (NULL == file) {
}
peasycap = file->private_data;
if (NULL == peasycap) {
SAY("ERROR: peasycap is NULL.\n");
SAY("ERROR: peasycap is NULL\n");
return -1;
}
if (memcmp(&peasycap->telltale[0], TELLTALE, strlen(TELLTALE))) {
SAY("ERROR: bad peasycap\n");
return -EFAULT;
}
p = peasycap->pusb_device;
if (NULL == p) {
SAM("ERROR: peasycap->pusb_device is NULL\n");
Expand Down Expand Up @@ -1012,6 +1016,11 @@ if (0 <= kd && DONGLE_MANY > kd) {
mutex_unlock(&easycap_dongle[kd].mutex_video);
return -ERESTARTSYS;
}
if (memcmp(&peasycap->telltale[0], TELLTALE, strlen(TELLTALE))) {
SAY("ERROR: bad peasycap\n");
mutex_unlock(&easycap_dongle[kd].mutex_video);
return -EFAULT;
}
p = peasycap->pusb_device;
if (NULL == peasycap->pusb_device) {
SAM("ERROR: peasycap->pusb_device is NULL\n");
Expand Down Expand Up @@ -2297,7 +2306,7 @@ case VIDIOC_DQBUF:
((long long int)(timeval.tv_sec - \
timeval2.tv_sec)) + \
(long long int)(timeval.tv_usec - \
timeval2.tv_usec);
timeval2.tv_usec);
sdr = signed_div(fudge, 1000);
sll = sdr.quotient;
ull = sdr.remainder;
Expand All @@ -2317,6 +2326,8 @@ case VIDIOC_DQBUF:
JOM(16, " %10i=bytesused\n", v4l2_buffer.bytesused);
JOM(16, " 0x%08X=flags\n", v4l2_buffer.flags);
JOM(16, " %10i=field\n", v4l2_buffer.field);
JOM(16, " %10li=timestamp.tv_sec\n", \
(long)v4l2_buffer.timestamp.tv_sec);
JOM(16, " %10li=timestamp.tv_usec\n", \
(long)v4l2_buffer.timestamp.tv_usec);
JOM(16, " %10i=sequence\n", v4l2_buffer.sequence);
Expand Down Expand Up @@ -2528,6 +2539,10 @@ if (NULL == peasycap) {
SAY("ERROR: peasycap is NULL.\n");
return -EFAULT;
}
if (memcmp(&peasycap->telltale[0], TELLTALE, strlen(TELLTALE))) {
SAY("ERROR: bad peasycap\n");
return -EFAULT;
}
p = peasycap->pusb_device;
if (NULL == p) {
SAM("ERROR: peasycap->pusb_device is NULL\n");
Expand Down Expand Up @@ -2560,6 +2575,11 @@ if (0 <= kd && DONGLE_MANY > kd) {
mutex_unlock(&easycap_dongle[kd].mutex_audio);
return -ERESTARTSYS;
}
if (memcmp(&peasycap->telltale[0], TELLTALE, strlen(TELLTALE))) {
SAY("ERROR: bad peasycap\n");
mutex_unlock(&easycap_dongle[kd].mutex_audio);
return -EFAULT;
}
p = peasycap->pusb_device;
if (NULL == peasycap->pusb_device) {
SAM("ERROR: peasycap->pusb_device is NULL\n");
Expand Down Expand Up @@ -2795,3 +2815,5 @@ mutex_unlock(&easycap_dongle[kd].mutex_audio);
return 0;
}
/*****************************************************************************/


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