Hi Sakari,
On 11/27/2014 09:41 AM, Sakari Ailus wrote:
Hi Jacek,
On Fri, Nov 21, 2014 at 05:14:40PM +0100, Jacek Anaszewski wrote:
The plugin provides support for the media device on Exynos4 SoC.
It performs single plane <-> multi plane API conversion,
video pipeline linking and takes care of automatic data format
negotiation for the whole pipeline, after intercepting
VIDIOC_S_FMT or VIDIOC_TRY_FMT ioctls.
[...]
+
+static void *plugin_init(int fd)
+{
+ struct v4l2_capability cap;
+ struct exynos4_camera_plugin *plugin = NULL;
+ const char *sink_entity_name;
+ struct media_device *media;
+ struct media_entity *sink_entity;
+ char video_devname[32];
+ int ret;
[...]
+ ret = SYS_IOCTL(fd, VIDIOC_QUERYCAP, &cap);
+ if (ret < 0) {
+ V4L2_EXYNOS4_ERR("Failed to query video capabilities.");
+ return NULL;
+ }
+
+ /* Check if this is Exynos4 media device */
+ if (strcmp((char *) cap.driver, EXYNOS4_FIMC_DRV) &&
+ strcmp((char *) cap.driver, EXYNOS4_FIMC_LITE_DRV) &&
+ strcmp((char *) cap.driver, EXYNOS4_FIMC_IS_ISP_DRV)) {
+ V4L2_EXYNOS4_ERR("Not an Exynos4 media device.");
+ return NULL;
+ }
+
+ /* Obtain the node name of the opened device */
+ ret = media_get_devname_by_fd(fd, video_devname);
+ if (ret < 0) {
+ V4L2_EXYNOS4_ERR("Failed to get video device node name.");
+ return NULL;
+ }
+
+ /*
+ * Create the representation of a media device
+ * containing the opened video device.
+ */
+ media = media_device_new_by_entity_devname(video_devname);
+ if (media == NULL) {
+ V4L2_EXYNOS4_ERR("Failed to create media device.");
+ return NULL;
+ }
+
+#ifdef DEBUG
+ media_debug_set_handler(media, (void (*)(void *, ...))fprintf, stdout);
+#endif
+
+ /* Get the entity representing the opened video device node */
+ sink_entity = media_get_entity_by_devname(media, video_devname,
strlen(video_devname));
Could you use the fd directly instead of translating that to the device
node? fstat(2) gives you directly inode / device major + minor which you can
then use to find the MC device.
After trying to switch it as you requested I decided to stay by current
implementation to avoid the need for translating fd to device node
twice.
If we changed:
media_device_new_by_entity_devname -> media_device_new_by_entity_fd
then media_device_new_by_entity_fd would have to call fstat to find
out the entity node name. Nonetheless we would have to call fstat
one more time to obtain sink_entity to be passed below to
media_entity_get_name.
Therefore, it is better to obtain devname once and use it for
both creating media_device and obtaining sink_entity node name.
+ if (sink_entity == NULL) {
+ V4L2_EXYNOS4_ERR("Failed to get sinkd entity name.");
+ goto err_get_sink_entity;
+ }
+
+ /* The last entity in the pipeline represents video device node */
+ media_entity_set_fd(sink_entity, fd);
+
+ sink_entity_name = media_entity_get_name(sink_entity);
+
+ /* Check if video entity is of capture type, not m2m */
+ if (!__capture_entity(sink_entity_name)) {
+ V4L2_EXYNOS4_ERR("Device not of capture type.");
+ goto err_get_sink_entity;
+ }
--
Best Regards,
Jacek Anaszewski
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