mirror of https://gitee.com/openkylin/linux.git
V4L/DVB (5972): ivtv: prevent yuv register updates from being missed
The yuv output code always compares the new frame position & size with those of the previous frame. If they are different, a flag is set to request the yuv output registers be updated when the new frame is displayed. If the incoming frames are delivered too fast, exhausting the buffers, the most recent frame already buffered will be discarded. Unfortunately, any update request will also be discarded. If the new frame matches the size & position of the now discarded frame, the yuv registers are not flagged for update & will remain in their old state. This patch preserves the register update flag in the event that a frame is dropped. Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk> Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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@ -940,6 +940,7 @@ int ivtv_yuv_prep_frame(struct ivtv *itv, struct ivtv_dma_frame *args)
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int rc = 0;
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int got_sig = 0;
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int frame, next_fill_frame, last_fill_frame;
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int register_update = 0;
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IVTV_DEBUG_INFO("yuv_prep_frame\n");
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@ -953,6 +954,7 @@ int ivtv_yuv_prep_frame(struct ivtv *itv, struct ivtv_dma_frame *args)
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/* Buffers are full - Overwrite the last frame */
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next_fill_frame = frame;
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frame = (frame - 1) & 3;
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register_update = itv->yuv_info.new_frame_info[frame].update;
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}
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/* Take a snapshot of the yuv coordinate information */
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@ -991,6 +993,8 @@ int ivtv_yuv_prep_frame(struct ivtv *itv, struct ivtv_dma_frame *args)
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/* IVTV_DEBUG_YUV ("Requesting register update for frame %d\n",frame); */
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}
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itv->yuv_info.new_frame_info[frame].update |= register_update;
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/* DMA the frame */
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mutex_lock(&itv->udma.lock);
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