On 3/25/19 12:20 PM, Tomasz Figa wrote: > On Mon, Mar 25, 2019 at 1:12 PM Bingbu Cao <bingbu.cao@xxxxxxxxxxxxxxx> wrote: >> >> >> >> On 3/25/19 11:16 AM, Tomasz Figa wrote: >>> Hi Bingbu, >>> >>> On Wed, Mar 13, 2019 at 1:25 PM Bingbu Cao <bingbu.cao@xxxxxxxxxxxxxxx> wrote: >>>> >>>> >>>> >>>> On 03/12/2019 04:54 PM, Tomasz Figa wrote: >>>>> On Tue, Mar 12, 2019 at 5:48 PM Bingbu Cao <bingbu.cao@xxxxxxxxxxxxxxx> wrote: >>>>>> >>>>>> >>>>>> On 03/12/2019 03:43 PM, Tomasz Figa wrote: >>>>>>> On Tue, Mar 12, 2019 at 3:48 PM Bingbu Cao <bingbu.cao@xxxxxxxxxxxxxxx> wrote: >>>>>>>> >>>>>>>> On 03/12/2019 01:33 PM, Tomasz Figa wrote: >>>>>>>>> Hi Bingbu, >>>>>>>>> >>>>>>>>> On Fri, Feb 15, 2019 at 6:02 PM <bingbu.cao@xxxxxxxxx> wrote: >>>>>>>>>> From: Bingbu Cao <bingbu.cao@xxxxxxxxx> >>>>>>>>>> >>>>>>>>>> Current ImgU driver processes and releases the parameter buffer >>>>>>>>>> immediately after queued from user. This does not align with other >>>>>>>>>> image buffers which are grouped in sets and used for the same frame. >>>>>>>>>> If user queues multiple parameter buffers continuously, only the last >>>>>>>>>> one will take effect. >>>>>>>>>> To make consistent buffers usage, this patch changes the parameter >>>>>>>>>> buffer handling and group parameter buffer with other image buffers >>>>>>>>>> for each frame. >>>>>>>>> Thanks for the patch. Please see my comments inline. >>>>>>>>> >>>>>>>>>> Signed-off-by: Tianshu Qiu <tian.shu.qiu@xxxxxxxxx> >>>>>>>>>> Signed-off-by: Bingbu Cao <bingbu.cao@xxxxxxxxx> >>>>>>>>>> --- >>>>>>>>>> drivers/staging/media/ipu3/ipu3-css.c | 5 ----- >>>>>>>>>> drivers/staging/media/ipu3/ipu3-v4l2.c | 41 ++++++++-------------------------- >>>>>>>>>> drivers/staging/media/ipu3/ipu3.c | 24 ++++++++++++++++++++ >>>>>>>>>> 3 files changed, 33 insertions(+), 37 deletions(-) >>>>>>>>>> >>>>>>>>>> diff --git a/drivers/staging/media/ipu3/ipu3-css.c b/drivers/staging/media/ipu3/ipu3-css.c >>>>>>>>>> index b9354d2bb692..bcb1d436bc98 100644 >>>>>>>>>> --- a/drivers/staging/media/ipu3/ipu3-css.c >>>>>>>>>> +++ b/drivers/staging/media/ipu3/ipu3-css.c >>>>>>>>>> @@ -2160,11 +2160,6 @@ int ipu3_css_set_parameters(struct ipu3_css *css, unsigned int pipe, >>>>>>>>>> obgrid_size = ipu3_css_fw_obgrid_size(bi); >>>>>>>>>> stripes = bi->info.isp.sp.iterator.num_stripes ? : 1; >>>>>>>>>> >>>>>>>>>> - /* >>>>>>>>>> - * TODO(b/118782861): If userspace queues more than 4 buffers, the >>>>>>>>>> - * parameters from previous buffers will be overwritten. Fix the driver >>>>>>>>>> - * not to allow this. >>>>>>>>>> - */ >>>>>>>>> Wouldn't this still happen even with current patch? >>>>>>>>> imgu_queue_buffers() supposedly queues "as many buffers to CSS as >>>>>>>>> possible". This means that if the userspace queues more than 4 >>>>>>>>> complete frames, we still end up overwriting the parameter buffers in >>>>>>>>> the pool. Please correct me if I'm wrong. >>>>>>>> The parameter buffers are queued to CSS sequentially and queue one >>>>>>>> parameter along with one input buffer once ready, all the data and >>>>>>>> parameter buffers are tied together to queue to the CSS. If userspace >>>>>>>> queue more parameter buffers then input buffer, they are pending on the >>>>>>>> buffer list. >>>>>>> It doesn't seem to be what the code does. I'm talking about the >>>>>>> following example: >>>>>>> >>>>>>> Queue OUT buffer 1 >>>>>>> Queue PARAM buffer 1 >>>>>>> Queue IN buffer 1 >>>>>>> Queue OUT buffer 2 >>>>>>> Queue PARAM buffer 2 >>>>>>> Queue IN buffer 2 >>>>>>> Queue OUT buffer 3 >>>>>>> Queue PARAM buffer 3 >>>>>>> Queue IN buffer 3 >>>>>>> Queue OUT buffer 4 >>>>>>> Queue PARAM buffer 4 >>>>>>> Queue IN buffer 4 >>>>>>> Queue OUT buffer 5 >>>>>>> Queue PARAM buffer 5 >>>>>>> Queue IN buffer 5 >>>>>>> >>>>>>> All the operations happening exactly one after each other. How would >>>>>>> the code prevent the 5th PARAM buffer to be queued to the IMGU, after >>>>>>> the 5th IN buffer is queued? As I said, imgu_queue_buffers() just >>>>>>> queues as many buffers of each type as there are IN buffers available. >>>>>> So the parameter pool now is only used as record last valid parameter not >>>>>> used as a list or cached, all the parameters will be queued to CSS as soon as >>>>>> possible(if queue for CSS is not full). >>>>>> As the size of pool now is a bit confusing, I think we can shrink the its value >>>>>> for each pipe to 2. >>>>> I don't follow. Don't we take one buffer from the pool, fill in the >>>>> parameters in hardware format there and then queue that buffer from >>>>> the pool to the ISP? The ISP wouldn't read those parameters from the >>>>> buffer until the previous frame is processed, would it? >>>> Hi, Tomasz, >>>> >>>> Currently, driver did not take the buffer from pool to queue to ISP, >>>> it just queue the parameter buffer along with input frame buffer depends >>>> on each user queue request. >>>> >>>> You are right, if user queue massive buffers one time, it will cause >>>> the firmware queue full. Driver should keep the buffer in its list >>>> instead of returning back to user irresponsibly. >>>> >>>> We are thinking about queue one group of buffers(input, output and params) >>>> to ISP one time and wait the pipeline finished and then queue next group >>>> of buffers. All the buffers are pending on the buffer list. >>>> What do you think about this behavior? >>> >>> Sorry, I was sure I replied to your email, but apparently I didn't. >>> >>> Yes, that would certainly work, but wouldn't it introduce pipeline >>> bubbles, potentially affecting the performance? >> Hi, Tomasz, >> >> Thanks for your reply. >> >> The driver will queue the buffers to CSS immediately after previous >> pipeline finished which is invoked in imgu_isr_threaded. >> >> The bubbles compared from before should be very small since current >> camera HAL implementation in production will queue new buffers IFF all >> the buffers dequeued from driver, as I know. > > If the firmware has a queue depth of 4, I think it would still be much > better to use it. Would it really make the code much more complicated? > I think you could just maintain a counter of queued buffers and keep > refilling the queue whenever it's less than 4 and there are any > buffers to queue. Actually, firmware will use latest parameter queued and apply to frame, they are not consumed frame by frame. The parameter buffers are not used same way as frame buffers, so the pool in driver is just used for storing previous parameter and refilling fields within new coming parameter from user and combine with previous ones into a whole parameter. >
