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[media] gspca: Add a need_max_bandwidth flag to sd_desc 

Some cameras will pretty much entirely fill all the image buffers all the
time even though they are using compression.

This patch adds a flag to sd_desc, which drivers for such cameras can set.

When this flag is set the bandwidth calculation code will no longer
assume that the image buffer size is a worst case and less bandwidth than
imagebufsize * fps will be used on average.

This patch sets this new flag for 3 drivers:
* For spca561 (for rev12a cameras) and nw80x cams as these simply don't work
  when given less bandwidth than imagebufsize * fps.
* For sn9c20x cameras, because these show severy jpeg artifacts when
  given less bandwidth than imagebufsize * fps and since these are usb2
  cameras there is plenty bandwidth anyways.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans de Goede 2012-01-01 16:35:01 -03:00 committed by Mauro Carvalho Chehab
parent 51e23be284
commit eb3fb7c963
5 changed files with 8 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/media/video/gspca/gspca.c
View File

@ -638,7 +638,8 @@ static u32 which_bandwidth(struct gspca_dev *gspca_dev)
bandwidth = gspca_dev->cam.cam_mode[i].sizeimage; bandwidth = gspca_dev->cam.cam_mode[i].sizeimage;
/* if the image is compressed, estimate its mean size */ /* if the image is compressed, estimate its mean size */
if (bandwidth < gspca_dev->cam.cam_mode[i].width * if (!gspca_dev->cam.needs_full_bandwidth &&
bandwidth < gspca_dev->cam.cam_mode[i].width *
gspca_dev->cam.cam_mode[i].height) gspca_dev->cam.cam_mode[i].height)
bandwidth = bandwidth * 3 / 8; /* 0.375 */ bandwidth = bandwidth * 3 / 8; /* 0.375 */

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

@ -69,6 +69,9 @@ struct cam {
u8 bulk; /* image transfer by 0:isoc / 1:bulk */ u8 bulk; /* image transfer by 0:isoc / 1:bulk */
u8 npkt; /* number of packets in an ISOC message u8 npkt; /* number of packets in an ISOC message
* 0 is the default value: 32 packets */ * 0 is the default value: 32 packets */
u8 needs_full_bandwidth;/* Set this flag to notify the bandwidth calc.
* code that the cam fills all image buffers to
* the max, even when using compression. */
}; };
struct gspca_dev; struct gspca_dev;

1
drivers/media/video/gspca/nw80x.c
View File

@ -1764,6 +1764,7 @@ static int sd_config(struct gspca_dev *gspca_dev,
webcam = 0; webcam = 0;
sd->webcam = webcam; sd->webcam = webcam;
gspca_dev->cam.ctrls = sd->ctrls; gspca_dev->cam.ctrls = sd->ctrls;
gspca_dev->cam.needs_full_bandwidth = 1;
sd->ag_cnt = -1; sd->ag_cnt = -1;
/* /*

1
drivers/media/video/gspca/sn9c20x.c
View File

@ -2048,6 +2048,7 @@ static int sd_config(struct gspca_dev *gspca_dev,
struct cam *cam; struct cam *cam;
cam = &gspca_dev->cam; cam = &gspca_dev->cam;
cam->needs_full_bandwidth = 1;
sd->sensor = (id->driver_info >> 8) & 0xff; sd->sensor = (id->driver_info >> 8) & 0xff;
sd->i2c_addr = id->driver_info & 0xff; sd->i2c_addr = id->driver_info & 0xff;

1
drivers/media/video/gspca/spca561.c
View File

@ -451,6 +451,7 @@ static int sd_config(struct gspca_dev *gspca_dev,
} }
cam = &gspca_dev->cam; cam = &gspca_dev->cam;
cam->needs_full_bandwidth = 1;
sd->chip_revision = id->driver_info; sd->chip_revision = id->driver_info;
if (sd->chip_revision == Rev012A) { if (sd->chip_revision == Rev012A) {