[PATCH 3/4] media: stm32-dcmi: clarify state logic on buffer starvation

[Hugues Fruchet]

Introduce WAIT_FOR_BUFFER state instead of "active" field checking
to manage buffer starvation case.

Signed-off-by: Hugues Fruchet <hugues.fruc...@st.com>
---
 drivers/media/platform/stm32/stm32-dcmi.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/stm32/stm32-dcmi.c 
b/drivers/media/platform/stm32/stm32-dcmi.c
index 6ccf195..93bb03a 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -85,6 +85,7 @@
 
 enum state {
        STOPPED = 0,
+       WAIT_FOR_BUFFER,
        RUNNING,
        STOPPING,
 };
@@ -230,6 +231,7 @@ static int dcmi_restart_capture(struct stm32_dcmi *dcmi)
        if (list_empty(&dcmi->buffers)) {
                dev_dbg(dcmi->dev, "Capture restart is deferred to next buffer 
queueing\n");
                dcmi->active = NULL;
+               dcmi->state = WAIT_FOR_BUFFER;
                spin_unlock_irq(&dcmi->irqlock);
                return 0;
        }
@@ -548,9 +550,11 @@ static void dcmi_buf_queue(struct vb2_buffer *vb)
 
        spin_lock_irq(&dcmi->irqlock);
 
-       if (dcmi->state == RUNNING && !dcmi->active) {
                dcmi->active = buf;
 
+       if (dcmi->state == WAIT_FOR_BUFFER) {
+               dcmi->state = RUNNING;
+
                dev_dbg(dcmi->dev, "Starting capture on buffer[%d] queued\n",
                        buf->vb.vb2_buf.index);
 
@@ -630,8 +634,6 @@ static int dcmi_start_streaming(struct vb2_queue *vq, 
unsigned int count)
        /* Enable dcmi */
        reg_set(dcmi->regs, DCMI_CR, CR_ENABLE);
 
-       dcmi->state = RUNNING;
-
        dcmi->sequence = 0;
        dcmi->errors_count = 0;
        dcmi->overrun_count = 0;
@@ -644,6 +646,7 @@ static int dcmi_start_streaming(struct vb2_queue *vq, 
unsigned int count)
         */
        if (list_empty(&dcmi->buffers)) {
                dev_dbg(dcmi->dev, "Start streaming is deferred to next buffer 
queueing\n");
+               dcmi->state = WAIT_FOR_BUFFER;
                spin_unlock_irq(&dcmi->irqlock);
                return 0;
        }
@@ -653,6 +656,8 @@ static int dcmi_start_streaming(struct vb2_queue *vq, 
unsigned int count)
 
        dev_dbg(dcmi->dev, "Start streaming, starting capture\n");
 
+       dcmi->state = RUNNING;
+
        spin_unlock_irq(&dcmi->irqlock);
        ret = dcmi_start_capture(dcmi);
        if (ret) {
-- 
1.9.1