git: 56d4dee82de1 - main - fwcam: defer ISO streaming to first read

The branch main has been updated by adrian:

URL: https://cgit.FreeBSD.org/src/commit/?id=56d4dee82de1b5c8c77d5be79f7bf4183b327b57

commit 56d4dee82de1b5c8c77d5be79f7bf4183b327b57
Author:     Abdelkader Boudih <freebsd@seuros.com>
AuthorDate: 2026-07-09 02:52:12 +0000
Commit:     Adrian Chadd <adrian@FreeBSD.org>
CommitDate: 2026-07-09 02:52:18 +0000

    fwcam: defer ISO streaming to first read
    
    Moved ISO start to first usage. Opening the device now
    only validates state and increments the open count, allowing info
    queries and mode changes without starting the camera. ISO streaming
    begins on demand when userland first reads frame data.
    This avoid the camera led to turn-on at attach.
    
    Reviewed by:    adrian
    Differential Revision:  https://reviews.freebsd.org/D58100
---
 sys/dev/firewire/fwcam.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/sys/dev/firewire/fwcam.c b/sys/dev/firewire/fwcam.c
index 27451316d613..c5e5cf545fe9 100644
--- a/sys/dev/firewire/fwcam.c
+++ b/sys/dev/firewire/fwcam.c
@@ -288,7 +288,7 @@ fwcam_probe_task(void *arg, int pending __unused)
 		sc->state = FWCAM_STATE_PROBED;
 		FWCAM_UNLOCK(sc);
 
-		if (sc->open_count > 0 &&
+		if (sc->dma_ch >= 0 &&
 		    sc->state != FWCAM_STATE_DETACHING)
 			fwcam_iso_start(sc);
 	}
@@ -601,7 +601,6 @@ static int
 fwcam_cdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
 {
 	struct fwcam_softc *sc = dev->si_drv1;
-	int err = 0;
 
 	FWCAM_LOCK(sc);
 	if (sc->state == FWCAM_STATE_DETACHING) {
@@ -615,18 +614,8 @@ fwcam_cdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
 	}
 
 	sc->open_count++;
-	if (sc->open_count == 1 && sc->state == FWCAM_STATE_PROBED) {
-		FWCAM_UNLOCK(sc);
-		err = fwcam_iso_start(sc);
-		if (err) {
-			FWCAM_LOCK(sc);
-			sc->open_count--;
-			FWCAM_UNLOCK(sc);
-		}
-	} else {
-		FWCAM_UNLOCK(sc);
-	}
-	return (err);
+	FWCAM_UNLOCK(sc);
+	return (0);
 }
 
 static int
@@ -657,6 +646,13 @@ fwcam_cdev_read(struct cdev *dev, struct uio *uio, int ioflag)
 	int err;
 
 	FWCAM_LOCK(sc);
+	if (sc->state == FWCAM_STATE_PROBED) {
+		FWCAM_UNLOCK(sc);
+		err = fwcam_iso_start(sc);
+		if (err)
+			return (err);
+		FWCAM_LOCK(sc);
+	}
 	while (!sc->frame_ready) {
 		if (sc->state != FWCAM_STATE_STREAMING) {
 			FWCAM_UNLOCK(sc);