[PATCH v3 10/10] media: aspeed: add a workaround to fix a silicon bug

[Eddie James <eajames@linux.vnet.ibm.com>]

On 6/12/19 2:17 AM, Hans Verkuil wrote:
> Eddie: ping!
>
> Regards,
>
> 	Hans
>
> On 6/6/19 2:53 AM, Jae Hyun Yoo wrote:
>> Hi Eddie,
>>
>> All patches in this series were queued to linux/media tree except this
>> one. Can you please review this patch?
>>
>> Thanks,
>> Jae
>>
>> On 5/31/2019 3:15 PM, Jae Hyun Yoo wrote:
>>> AST2500 silicon revision A1 and A2 have a silicon bug which causes
>>> extremly long capturing time on specific resolutions (1680 width).
>>> To fix the bug, this commit adjusts the capturing window register
>>> setting to 1728 if detected width is 1680. The compression window
>>> register setting will be kept as the original width so output
>>> result will be the same.


Sorry, missed your followup email Jae and assumed everything was merged.


Looks fine to me.

Reviewed-by: Eddie James <eajames@linux.ibm.com>


>>>
>>> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
>>> ---
>>> v2 -> v3:
>>>    Added more detail comments why the value 1728 is picked.
>>>
>>> v1 -> v2:
>>>    New.
>>>
>>>    drivers/media/platform/aspeed-video.c | 28 ++++++++++++++++++++-------
>>>    1 file changed, 21 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
>>> index ba093096a5a7..f899ac3b4a61 100644
>>> --- a/drivers/media/platform/aspeed-video.c
>>> +++ b/drivers/media/platform/aspeed-video.c
>>> @@ -824,8 +824,29 @@ static void aspeed_video_set_resolution(struct aspeed_video *video)
>>>    	struct v4l2_bt_timings *act = &video->active_timings;
>>>    	unsigned int size = act->width * act->height;
>>>    
>>> +	/* Set capture/compression frame sizes */
>>>    	aspeed_video_calc_compressed_size(video, size);
>>>    
>>> +	if (video->active_timings.width == 1680) {
>>> +		/*
>>> +		 * This is a workaround to fix a silicon bug on A1 and A2
>>> +		 * revisions. Since it doesn't break capturing operation of
>>> +		 * other revisions, use it for all revisions without checking
>>> +		 * the revision ID. It picked 1728 which is a very next
>>> +		 * 64-pixels aligned value to 1680 to minimize memory bandwidth
>>> +		 * and to get better access speed from video engine.
>>> +		 */
>>> +		aspeed_video_write(video, VE_CAP_WINDOW,
>>> +				   1728 << 16 | act->height);
>>> +		size += (1728 - 1680) * video->active_timings.height;
>>> +	} else {
>>> +		aspeed_video_write(video, VE_CAP_WINDOW,
>>> +				   act->width << 16 | act->height);
>>> +	}
>>> +	aspeed_video_write(video, VE_COMP_WINDOW,
>>> +			   act->width << 16 | act->height);
>>> +	aspeed_video_write(video, VE_SRC_SCANLINE_OFFSET, act->width * 4);
>>> +
>>>    	/* Don't use direct mode below 1024 x 768 (irqs don't fire) */
>>>    	if (size < DIRECT_FETCH_THRESHOLD) {
>>>    		aspeed_video_write(video, VE_TGS_0,
>>> @@ -842,13 +863,6 @@ static void aspeed_video_set_resolution(struct aspeed_video *video)
>>>    		aspeed_video_update(video, VE_CTRL, 0, VE_CTRL_DIRECT_FETCH);
>>>    	}
>>>    
>>> -	/* Set capture/compression frame sizes */
>>> -	aspeed_video_write(video, VE_CAP_WINDOW,
>>> -			   act->width << 16 | act->height);
>>> -	aspeed_video_write(video, VE_COMP_WINDOW,
>>> -			   act->width << 16 | act->height);
>>> -	aspeed_video_write(video, VE_SRC_SCANLINE_OFFSET, act->width * 4);
>>> -
>>>    	size *= 4;
>>>    
>>>    	if (size != video->srcs[0].size) {
>>>