ibmcam.txt

Linux Kernel 2.6.9 for OMAP1710

Module can be inserted with camera connected or disconnected.

The driver can have options, though some defaults are provided.

Driver options: (* indicates that option is model-dependent)

Name            Type            Range [default] Example
--------------  --------------  --------------  ------------------
debug           Integer         0-9 [0]         debug=1
flags           Integer         0-0xFF [0]      flags=0x0d
framerate       Integer         0-6 [2]         framerate=1
hue_correction  Integer         0-255 [128]     hue_correction=115
init_brightness Integer         0-255 [128]     init_brightness=100
init_contrast   Integer         0-255 [192]     init_contrast=200
init_color      Integer         0-255 [128]     init_color=130
init_hue        Integer         0-255 [128]     init_hue=115
lighting        Integer         0-2* [1]        lighting=2
sharpness       Integer         0-6* [4]        sharpness=3
size            Integer         0-2* [2]        size=1

Options for Model 2 only:

Name            Type            Range [default] Example
--------------  --------------  --------------  ------------------
init_model2_rg  Integer         0..255 [0x70]   init_model2_rg=128
init_model2_rg2 Integer         0..255 [0x2f]   init_model2_rg2=50
init_model2_sat Integer         0..255 [0x34]   init_model2_sat=65
init_model2_yb  Integer         0..255 [0xa0]   init_model2_yb=200

debug           You don't need this option unless you are a developer.
                If you are a developer then you will see in the code
                what values do what. 0=off.

flags           This is a bit mask, and you can combine any number of
                bits to produce what you want. Usually you don't want
                any of extra features this option provides:

                FLAGS_RETRY_VIDIOCSYNC  1  This bit allows to retry failed
                                           VIDIOCSYNC ioctls without failing.
                                           Will work with xawtv, will not
                                           with xrealproducer. Default is
                                           not set.
                FLAGS_MONOCHROME        2  Activates monochrome (b/w) mode.
                FLAGS_DISPLAY_HINTS     4  Shows colored pixels which have
                                           magic meaning to developers.
                FLAGS_OVERLAY_STATS     8  Shows tiny numbers on screen,
                                           useful only for debugging.
                FLAGS_FORCE_TESTPATTERN 16 Shows blue screen with numbers.
                FLAGS_SEPARATE_FRAMES   32 Shows each frame separately, as
                                           it was received from the camera.
                                           Default (not set) is to mix the
                                           preceding frame in to compensate
                                           for occasional loss of Isoc data
                                           on high frame rates.
                FLAGS_CLEAN_FRAMES      64 Forces "cleanup" of each frame
                                           prior to use; relevant only if
                                           FLAGS_SEPARATE_FRAMES is set.
                                           Default is not to clean frames,
                                           this is a little faster but may
                                           produce flicker if frame rate is
                                           too high and Isoc data gets lost.
                FLAGS_NO_DECODING      128 This flag turns the video stream
                                           decoder off, and dumps the raw
                                           Isoc data from the camera into
                                           the reading process. Useful to
                                           developers, but not to users.

framerate       This setting controls frame rate of the camera. This is
                an approximate setting (in terms of "worst" ... "best")
                because camera changes frame rate depending on amount
                of light available. Setting 0 is slowest, 6 is fastest.
                Beware - fast settings are very demanding and may not
                work well with all video sizes. Be conservative.

hue_correction  This highly optional setting allows to adjust the
                hue of the image in a way slightly different from
                what usual "hue" control does. Both controls affect
                YUV colorspace: regular "hue" control adjusts only
                U component, and this "hue_correction" option similarly
                adjusts only V component. However usually it is enough
                to tweak only U or V to compensate for colored light or
                color temperature; this option simply allows more
                complicated correction when and if it is necessary.

init_brightness These settings specify _initial_ values which will be
init_contrast   used to set up the camera. If your V4L application has
init_color      its own controls to adjust the picture then these
init_hue        controls will be used too. These options allow you to
                preconfigure the camera when it gets connected, before
                any V4L application connects to it. Good for webcams.

init_model2_rg  These initial settings alter color balance of the
init_model2_rg2 camera on hardware level. All four settings may be used
init_model2_sat to tune the camera to specific lighting conditions. These
init_model2_yb  settings only apply to Model 2 cameras.

lighting        This option selects one of three hardware-defined
                photosensitivity settings of the camera. 0=bright light,
                1=Medium (default), 2=Low light. This setting affects
                frame rate: the dimmer the lighting the lower the frame
                rate (because longer exposition time is needed). The
                Model 2 cameras allow values more than 2 for this option,
                thus enabling extremely high sensitivity at cost of frame
                rate, color saturation and imaging sensor noise.

sharpness       This option controls smoothing (noise reduction)
                made by camera. Setting 0 is most smooth, setting 6
                is most sharp. Be aware that CMOS sensor used in the
                camera is pretty noisy, so if you choose 6 you will
                be greeted with "snowy" image. Default is 4. Model 2
                cameras do not support this feature.

size            This setting chooses one of several image sizes that are
                supported by this driver. Cameras may support more, but
                it's difficult to reverse-engineer all formats.
                Following video sizes are supported:

                size=0     128x96  (Model 1 only)
                size=1     160x120
                size=2     176x144
                size=3     320x240 (Model 2 only)
                size=4     352x240 (Model 2 only)
                size=5     352x288
                size=6     640x480 (Model 3 only)

                The 352x288 is the native size of the Model 1 sensor
                array, so it's the best resolution the camera can
                yield. The best resolution of Model 2 is 176x144, and
                larger images are produced by stretching the bitmap.
                Model 3 has sensor with 640x480 grid, and it works too,
                but the frame rate will be exceptionally low (1-2 FPS);
                it may be still OK for some applications, like security.
                Choose the image size you need. The smaller image can
                support faster frame rate. Default is 352x288.

For more information and the Troubleshooting FAQ visit this URL:

                http://www.linux-usb.org/ibmcam/

WHAT NEEDS TO BE DONE:

- The button on the camera is not used. I don't know how to get to it.
  I know now how to read button on Model 2, but what to do with it?

- Camera reports its status back to the driver; however I don't know
  what returned data means. If camera fails at some initialization
  stage then something should be done, and I don't do that because
  I don't even know that some command failed. This is mostly Model 1
  concern because Model 2 uses different commands which do not return
  status (and seem to complete successfully every time).

- Some flavors of Model 4 NetCameras produce only compressed video
  streams, and I don't know how to decode them.

CREDITS:

The code is based in no small part on the CPiA driver by Johannes Erdfelt,
Randy Dunlap, and others. Big thanks to them for their pioneering work on that
and the USB stack.

I also thank John Lightsey for his donation of the Veo Stingray camera.