V4L: ivtv: Add locking to ensure stream setup is atomic

Starting an MPEG and VBI capture simultaneously caused errors in
the VBI setup: this setup was done twice when it should be done
only for the first stream that is opened.
Added a mutex to prevent this from happening.

(cherry picked from commit f885969196da6ae905162c0d1c5f0553de12cb40)

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>

diff --git a/drivers/media/video/ivtv/ivtv-driver.c b/drivers/media/video/ivtv/ivtv-driver.c
index efc66355339ac7f8aa6d693c753c20afd006b594..5d9de5dc033b98488a48f0b719bd7b9fb566d3b2 100644 (file)
--- a/drivers/media/video/ivtv/ivtv-driver.c
+++ b/drivers/media/video/ivtv/ivtv-driver.c
@@ -622,6 +622,7 @@ static int __devinit ivtv_init_struct1(struct ivtv *itv)
        itv->enc_mbox.max_mbox = 2; /* the encoder has 3 mailboxes (0-2) */
        itv->dec_mbox.max_mbox = 1; /* the decoder has 2 mailboxes (0-1) */
 
+       mutex_init(&itv->serialize_lock);
        mutex_init(&itv->i2c_bus_lock);
        mutex_init(&itv->udma.lock);
 

diff --git a/drivers/media/video/ivtv/ivtv-driver.h b/drivers/media/video/ivtv/ivtv-driver.h
index 48afd4270cbfa119bfdd4df9f2fdaec794e48785..65ebddab3fe14522057c8c911423f487122bfb4a 100644 (file)
--- a/drivers/media/video/ivtv/ivtv-driver.h
+++ b/drivers/media/video/ivtv/ivtv-driver.h
@@ -722,6 +722,7 @@ struct ivtv {
        int search_pack_header;
 
        spinlock_t dma_reg_lock; /* lock access to DMA engine registers */
+       struct mutex serialize_lock;  /* lock used to serialize starting streams */
 
        /* User based DMA for OSD */
        struct ivtv_user_dma udma;

diff --git a/drivers/media/video/ivtv/ivtv-streams.c b/drivers/media/video/ivtv/ivtv-streams.c
index 6af88ae9295f8f4096ef3b8b230fba06ce9a4d48..d538efaf61c9dd0476ea53303593550b9bcfe26d 100644 (file)
--- a/drivers/media/video/ivtv/ivtv-streams.c
+++ b/drivers/media/video/ivtv/ivtv-streams.c
@@ -446,6 +446,9 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
        if (s->v4l2dev == NULL)
                return -EINVAL;
 
+       /* Big serialization lock to ensure no two streams are started
+          simultaneously: that can give all sorts of weird results. */
+       mutex_lock(&itv->serialize_lock);
        IVTV_DEBUG_INFO("Start encoder stream %s\n", s->name);
 
        switch (s->type) {
@@ -487,6 +490,7 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
                        0, sizeof(itv->vbi.sliced_mpeg_size));
                break;
        default:
+               mutex_unlock(&itv->serialize_lock);
                return -EINVAL;
        }
        s->subtype = subtype;
@@ -568,6 +572,7 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
        if (ivtv_vapi(itv, CX2341X_ENC_START_CAPTURE, 2, captype, subtype))
        {
                IVTV_DEBUG_WARN( "Error starting capture!\n");
+               mutex_unlock(&itv->serialize_lock);
                return -EINVAL;
        }
 
@@ -583,6 +588,7 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
 
        /* you're live! sit back and await interrupts :) */
        atomic_inc(&itv->capturing);
+       mutex_unlock(&itv->serialize_lock);
        return 0;
 }
 
@@ -762,17 +768,6 @@ int ivtv_stop_v4l2_encode_stream(struct ivtv_stream *s, int gop_end)
        /* when: 0 =  end of GOP  1 = NOW!, type: 0 = mpeg, subtype: 3 = video+audio */
        ivtv_vapi(itv, CX2341X_ENC_STOP_CAPTURE, 3, stopmode, cap_type, s->subtype);
 
-       /* only run these if we're shutting down the last cap */
-       if (atomic_read(&itv->capturing) - 1 == 0) {
-               /* event notification (off) */
-               if (test_and_clear_bit(IVTV_F_I_DIG_RST, &itv->i_flags)) {
-                       /* type: 0 = refresh */
-                       /* on/off: 0 = off, intr: 0x10000000, mbox_id: -1: none */
-                       ivtv_vapi(itv, CX2341X_ENC_SET_EVENT_NOTIFICATION, 4, 0, 0, IVTV_IRQ_ENC_VIM_RST, -1);
-                       ivtv_set_irq_mask(itv, IVTV_IRQ_ENC_VIM_RST);
-               }
-       }
-
        then = jiffies;
 
        if (!test_bit(IVTV_F_S_PASSTHROUGH, &s->s_flags)) {
@@ -840,17 +835,30 @@ int ivtv_stop_v4l2_encode_stream(struct ivtv_stream *s, int gop_end)
        /* Clear capture and no-read bits */
        clear_bit(IVTV_F_S_STREAMING, &s->s_flags);
 
+       /* ensure these global cleanup actions are done only once */
+       mutex_lock(&itv->serialize_lock);
+
        if (s->type == IVTV_ENC_STREAM_TYPE_VBI)
                ivtv_set_irq_mask(itv, IVTV_IRQ_ENC_VBI_CAP);
 
        if (atomic_read(&itv->capturing) > 0) {
+               mutex_unlock(&itv->serialize_lock);
                return 0;
        }
 
        /* Set the following Interrupt mask bits for capture */
        ivtv_set_irq_mask(itv, IVTV_IRQ_MASK_CAPTURE);
 
+       /* event notification (off) */
+       if (test_and_clear_bit(IVTV_F_I_DIG_RST, &itv->i_flags)) {
+               /* type: 0 = refresh */
+               /* on/off: 0 = off, intr: 0x10000000, mbox_id: -1: none */
+               ivtv_vapi(itv, CX2341X_ENC_SET_EVENT_NOTIFICATION, 4, 0, 0, IVTV_IRQ_ENC_VIM_RST, -1);
+               ivtv_set_irq_mask(itv, IVTV_IRQ_ENC_VIM_RST);
+       }
+
        wake_up(&s->waitq);
+       mutex_unlock(&itv->serialize_lock);
 
        return 0;
 }