[PATCH] media: mtk-jpeg: fix continuous log "Context is NULL"

[Rick Chang]

On Tue, 2017-03-14 at 22:21 +0800, Minghsiu Tsai wrote:
> The symptom is continuous log "mtk-jpeg 18004000.jpegdec: Context is NULL"
> in kernel log. It is becauese the error handling in irq doesn't clear
> interrupt.
> 
> The calling flow like as below when issue happen
> mtk_jpeg_device_run()
> mtk_jpeg_job_abort()
>   v4l2_m2m_job_finish() -> m2m_dev->curr_ctx = NULL;
> mtk_jpeg_dec_irq()
>   v4l2_m2m_get_curr_priv()
>      -> m2m_dev->curr_ctx == NULL
>      -> return NULL
> log "Context is NULL"
> 
> There is race condition between job_abort() and irq. In order to simplify
> code, don't want to add extra flag to maintain state, empty job_abort() and
> clear interrupt before v4l2_m2m_get_curr_priv() in irq.
> 
> Signed-off-by: Minghsiu Tsai <minghsiu.tsai at mediatek.com>
> ---
>  drivers/media/platform/mtk-jpeg/mtk_jpeg_core.c | 14 ++------------
>  1 file changed, 2 insertions(+), 12 deletions(-)
Acked-by: Rick Chang <rick.chang at mediatek.com>