[FFmpeg-devel] [PATCH 3/3] avcodec: v4l2_m2m: context: fix raising warning on POLLERR

[Jorge Ramirez-Ortiz]

From: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz at linaro.org>

During the initialization stage, the codec attempts to get free
buffers from the driver before any have been queued (this is to keep
the code simple and generic)

When the kernel driver detects this situation, it returns POLLERR in
revents and ffmpeg therefore raises a warning.

This commit disables the warning since no buffers were queued to the
driver yet.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz at linaro.org>
---
 libavcodec/v4l2_context.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c
index fb482cf..5bacaaf 100644
--- a/libavcodec/v4l2_context.c
+++ b/libavcodec/v4l2_context.c
@@ -258,7 +258,7 @@ static V4L2Buffer* v4l2_dequeue_v4l2buf(V4L2Context *ctx, int timeout)
         .events =  POLLIN | POLLRDNORM | POLLPRI | POLLOUT | POLLWRNORM, /* default blocking capture */
         .fd = ctx_to_m2mctx(ctx)->fd,
     };
-    int ret;
+    int i, ret;
 
     if (V4L2_TYPE_IS_OUTPUT(ctx->type))
         pfd.events =  POLLOUT | POLLWRNORM;
@@ -279,7 +279,19 @@ static V4L2Buffer* v4l2_dequeue_v4l2buf(V4L2Context *ctx, int timeout)
 
     /* 0. handle errors */
     if (pfd.revents & POLLERR) {
-        av_log(logger(ctx), AV_LOG_WARNING, "%s POLLERR\n", ctx->name);
+	    /* if we are trying to get free buffers but none have been queued yet
+	       no need to raise a warning */
+	    if (timeout == 0 ) {
+		for (i = 0; i < ctx->num_buffers; i++) {
+			if (ctx->buffers[i].status != V4L2BUF_AVAILABLE) {
+				av_log(logger(ctx), AV_LOG_WARNING, "%s POLLERR\n", ctx->name);
+				return NULL;
+			}
+		}
+	    }
+	    else
+		    av_log(logger(ctx), AV_LOG_WARNING, "%s POLLERR\n", ctx->name);
+
         return NULL;
     }
 
-- 
2.7.4