libv4l: detect (usb) connection speed

And use it for determining the optimal source format.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/lib/libv4lconvert/control/libv4lcontrol-priv.h b/lib/libv4lconvert/control/libv4lcontrol-priv.h
index 22cdf34..2807c3a 100644 (file)
--- a/lib/libv4lconvert/control/libv4lcontrol-priv.h
+++ b/lib/libv4lconvert/control/libv4lcontrol-priv.h
@@ -31,6 +31,7 @@ struct v4lcontrol_flags_info;
 
 struct v4lcontrol_data {
        int fd;                   /* Device fd */
+       int bandwidth;            /* Connection bandwidth (0 = unknown) */
        int flags;                /* Flags for this device */
        int priv_flags;           /* Internal use only flags */
        int controls;             /* Which controls to use for this device */

diff --git a/lib/libv4lconvert/control/libv4lcontrol.c b/lib/libv4lconvert/control/libv4lcontrol.c
index 6b3be9b..2b7a33b 100644 (file)
--- a/lib/libv4lconvert/control/libv4lcontrol.c
+++ b/lib/libv4lconvert/control/libv4lcontrol.c
@@ -627,8 +627,9 @@ static void v4lcontrol_get_dmi_string(const char *string, char *buf, int size)
        fclose(f);
 }
 
-static int v4lcontrol_get_usb_ids(struct v4lcontrol_data *data,
-               unsigned short *vendor_id, unsigned short *product_id)
+static int v4lcontrol_get_usb_info(struct v4lcontrol_data *data,
+               unsigned short *vendor_id, unsigned short *product_id,
+               int *speed)
 {
        FILE *f;
        int i, minor;
@@ -642,7 +643,7 @@ static int v4lcontrol_get_usb_ids(struct v4lcontrol_data *data,
        /* <Sigh> find ourselve in sysfs */
        for (i = 0; i < 256; i++) {
                snprintf(sysfs_name, sizeof(sysfs_name),
-                               "/sys/class/video4linux/video%d/dev", i);
+                        "/sys/class/video4linux/video%d/dev", i);
                f = fopen(sysfs_name, "r");
                if (!f)
                        continue;
@@ -650,8 +651,8 @@ static int v4lcontrol_get_usb_ids(struct v4lcontrol_data *data,
                s = fgets(buf, sizeof(buf), f);
                fclose(f);
 
-               if (s && sscanf(buf, "%*d:%d%c", &minor, &c) == 2 && c == '\n' &&
-                               minor == minor(st.st_rdev))
+               if (s && sscanf(buf, "%*d:%d%c", &minor, &c) == 2 &&
+                   c == '\n' && minor == minor(st.st_rdev))
                        break;
        }
        if (i == 256)
@@ -659,23 +660,26 @@ static int v4lcontrol_get_usb_ids(struct v4lcontrol_data *data,
 
        /* Get vendor and product ID */
        snprintf(sysfs_name, sizeof(sysfs_name),
-                       "/sys/class/video4linux/video%d/device/modalias", i);
+                "/sys/class/video4linux/video%d/device/modalias", i);
        f = fopen(sysfs_name, "r");
        if (f) {
                s = fgets(buf, sizeof(buf), f);
                fclose(f);
 
-               if (!s || sscanf(s, "usb:v%4hxp%4hx%c", vendor_id, product_id, &c) != 3 ||
-                               c != 'd')
+               if (!s || sscanf(s, "usb:v%4hxp%4hx%c", vendor_id, product_id,
+                                &c) != 3 || c != 'd')
                        return 0; /* Not an USB device */
+
+               snprintf(sysfs_name, sizeof(sysfs_name),
+                        "/sys/class/video4linux/video%d/device/../speed", i);
        } else {
                /* Try again assuming the device link points to the usb
                   device instead of the usb interface (bug in older versions
                   of gspca) */
 
-               /* Get product ID */
+               /* Get vendor ID */
                snprintf(sysfs_name, sizeof(sysfs_name),
-                               "/sys/class/video4linux/video%d/device/idVendor", i);
+                        "/sys/class/video4linux/video%d/device/idVendor", i);
                f = fopen(sysfs_name, "r");
                if (!f)
                        return 0; /* Not an USB device (or no sysfs) */
@@ -683,12 +687,13 @@ static int v4lcontrol_get_usb_ids(struct v4lcontrol_data *data,
                s = fgets(buf, sizeof(buf), f);
                fclose(f);
 
-               if (!s || sscanf(s, "%04hx%c", vendor_id, &c) != 2 || c != '\n')
+               if (!s || sscanf(s, "%04hx%c", vendor_id, &c) != 2 ||
+                   c != '\n')
                        return 0; /* Should never happen */
 
                /* Get product ID */
                snprintf(sysfs_name, sizeof(sysfs_name),
-                               "/sys/class/video4linux/video%d/device/idProduct", i);
+                        "/sys/class/video4linux/video%d/device/idProduct", i);
                f = fopen(sysfs_name, "r");
                if (!f)
                        return 0; /* Should never happen */
@@ -696,10 +701,24 @@ static int v4lcontrol_get_usb_ids(struct v4lcontrol_data *data,
                s = fgets(buf, sizeof(buf), f);
                fclose(f);
 
-               if (!s || sscanf(s, "%04hx%c", product_id, &c) != 2 || c != '\n')
+               if (!s || sscanf(s, "%04hx%c", product_id, &c) != 2 ||
+                   c != '\n')
                        return 0; /* Should never happen */
+
+               snprintf(sysfs_name, sizeof(sysfs_name),
+                        "/sys/class/video4linux/video%d/device/speed", i);
        }
 
+       f = fopen(sysfs_name, "r");
+       if (!f)
+               return 0; /* Should never happen */
+
+       s = fgets(buf, sizeof(buf), f);
+       fclose(f);
+
+       if (!s || sscanf(s, "%d%c", speed, &c) != 2 || (c != '\n' && c != '.'))
+               return 0; /* Should never happen */
+
        return 1;
 }
 
@@ -752,7 +771,7 @@ static void v4lcontrol_get_flags_from_db(struct v4lcontrol_data *data,
 struct v4lcontrol_data *v4lcontrol_create(int fd, int always_needs_conversion)
 {
        int shm_fd;
-       int i, rc, got_usb_ids, init = 0;
+       int i, rc, got_usb_info, speed, init = 0;
        char *s, shm_name[256], pwd_buf[1024];
        struct v4l2_capability cap;
        struct v4l2_queryctrl ctrl;
@@ -779,9 +798,26 @@ struct v4lcontrol_data *v4lcontrol_create(int fd, int always_needs_conversion)
                        data->flags |= V4LCONTROL_VFLIPPED;
        }
 
-       got_usb_ids = v4lcontrol_get_usb_ids(data, &vendor_id, &product_id);
-       if (got_usb_ids)
+       got_usb_info = v4lcontrol_get_usb_info(data, &vendor_id, &product_id,
+                                              &speed);
+       if (got_usb_info) {
                v4lcontrol_get_flags_from_db(data, vendor_id, product_id);
+               switch (speed) {
+               case 12:
+                       data->bandwidth = 1023 * 1000;
+                       break;
+               case 480:
+                       data->bandwidth = 3 * 1024 * 8000;
+                       break;
+               case 5000:
+                       data->bandwidth = 48 * 1024 * 8000;
+                       break;
+               default:
+                       /* heuh, low speed device, or ... ? */
+                       data->bandwidth = speed / 20;
+               }
+       } else
+               data->bandwidth = 0;
 
        /* Allow overriding through environment */
        s = getenv("LIBV4LCONTROL_FLAGS");
@@ -842,7 +878,7 @@ struct v4lcontrol_data *v4lcontrol_create(int fd, int always_needs_conversion)
        }
 
        if (getpwuid_r(geteuid(), &pwd, pwd_buf, sizeof(pwd_buf), &pwd_p) == 0) {
-               if (got_usb_ids)
+               if (got_usb_info)
                        snprintf(shm_name, 256, "/libv4l-%s:%s:%04x:%04x:%s", pwd.pw_name,
                                        cap.bus_info, (int)vendor_id, (int)product_id, cap.card);
                else
@@ -850,7 +886,7 @@ struct v4lcontrol_data *v4lcontrol_create(int fd, int always_needs_conversion)
                                        cap.bus_info, cap.card);
        } else {
                perror("libv4lcontrol: error getting username using uid instead");
-               if (got_usb_ids)
+               if (got_usb_info)
                        snprintf(shm_name, 256, "/libv4l-%lu:%s:%04x:%04x:%s",
                                        (unsigned long)geteuid(), cap.bus_info,
                                        (int)vendor_id, (int)product_id, cap.card);
@@ -1083,6 +1119,11 @@ int v4lcontrol_vidioc_s_ctrl(struct v4lcontrol_data *data, void *arg)
        return SYS_IOCTL(data->fd, VIDIOC_S_CTRL, arg);
 }
 
+int v4lcontrol_get_bandwidth(struct v4lcontrol_data *data)
+{
+       return data->bandwidth;
+}
+
 int v4lcontrol_get_flags(struct v4lcontrol_data *data)
 {
        return data->flags;

diff --git a/lib/libv4lconvert/control/libv4lcontrol.h b/lib/libv4lconvert/control/libv4lcontrol.h
index 974e97a..2543011 100644 (file)
--- a/lib/libv4lconvert/control/libv4lcontrol.h
+++ b/lib/libv4lconvert/control/libv4lcontrol.h
@@ -50,6 +50,8 @@ struct v4lcontrol_data;
 struct v4lcontrol_data *v4lcontrol_create(int fd, int always_needs_conversion);
 void v4lcontrol_destroy(struct v4lcontrol_data *data);
 
+int v4lcontrol_get_bandwidth(struct v4lcontrol_data *data);
+
 /* Functions used by v4lprocessing to get the control state */
 int v4lcontrol_get_flags(struct v4lcontrol_data *data);
 int v4lcontrol_get_ctrl(struct v4lcontrol_data *data, int ctrl);

diff --git a/lib/libv4lconvert/libv4lconvert.c b/lib/libv4lconvert/libv4lconvert.c
index 7caa758..1a5f0be 100644 (file)
--- a/lib/libv4lconvert/libv4lconvert.c
+++ b/lib/libv4lconvert/libv4lconvert.c
@@ -117,8 +117,6 @@ struct v4lconvert_data *v4lconvert_create(int fd)
 
        data->fd = fd;
        data->decompress_pid = -1;
-       /* Default to usb 2 bandwidth and 30 fps for now */
-       data->bandwidth = 3 * 1024 * 8000; /* 3 * 1024 byte packets * 8000 microframes */
        data->fps = 30;
 
        /* Check supported formats */
@@ -160,6 +158,7 @@ struct v4lconvert_data *v4lconvert_create(int fd)
                return NULL;
        }
        data->control_flags = v4lcontrol_get_flags(data->control);
+       data->bandwidth = v4lcontrol_get_bandwidth(data->control);
 
        data->processing = v4lprocessing_create(fd, data->control);
        if (!data->processing) {
@@ -287,7 +286,7 @@ static int v4lconvert_get_rank(struct v4lconvert_data *data,
        /* check bandwidth needed */
        needed = src_width * src_height * data->fps *
                 supported_src_pixfmts[src_index].bpp / 8;
-       if (needed > data->bandwidth)
+       if (data->bandwidth && needed > data->bandwidth)
                rank += 10;
 #if 0
        printf("ranked: %c%c%c%c for %dx%d @ %d fps, needed: %d, bandwidth: %d, rank: %d\n",