Amlogic provide only 2.6.34 driver
can I expect big performance loss ?
On Tue, Apr 9, 2013 at 11:09 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> On Tue 9 April 2013 10:52:41 Michal Lazo wrote:
>> As we have all source codes
>> what do you advice ?
>
> Write your own driver. Good templates to look at are drivers/media/pci/sta2x11
> and drivers/media/platform/blackfin.
>
> The first is functionality-wise probably closer to what you need, but it's a pci
> driver, so the blackfin platform driver can be used to look at the platform part.
>
> Pick as recent a kernel as you can, but 3.6 at minimum since it has the useful
> vb2 helper functions that the sta2x11 driver also uses.
>
> Regards,
>
> Hans
>
>>
>>
>> On Tue, Apr 9, 2013 at 10:38 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
>> > On Tue 9 April 2013 09:58:33 Michal Lazo wrote:
>> >> I want to make API that will provide hw video decoder on Amlogic SOC
>> >> it is ARM cortex 9
>> >>
>> >> with some proprietary video decoder
>> >>
>> >> amlogic provide me with working example that generate output frames in
>> >> amlvideo driver.
>> >> It is v4l2 driver
>> >> and it did memcpy to mmap userspace memory
>> >>
>> >> buffer_y_start=ioremap(cs0.addr,cs0.width*cs0.height);
>> >> for(i=0;i<buf->vb.height;i++) {
>> >> memcpy(vbuf + pos_dst, buffer_y_start+pos_src, buf->vb.width*3);
>> >> pos_dst+=buf->vb.width*3;
>> >> pos_src+= cs0.width;
>> >> }
>> >>
>> >> I did it with one memcpy with same cpu load
>> >>
>> >> https://github.com/Pivosgroup/buildroot-linux-kernel/blob/master/drivers/media/video/amlvideo/amlvideo.c#L218
>> >>
>> >> top get me 50% cpu load on this driver for 25fps PAL
>> >>
>> >> it is really too much
>> >>
>> >> and funny is that vivi driver(amlvideo is completely base on vivi) get
>> >> me same cpu load
>> >
>> > Well, yes, because it is the memcpy that gives you all the load.
>> > Of course, in a well-written driver the amlvideo buffers would be available
>> > to userspace directly using mmap() and no memcpy would be needed.
>> >
>> > Basically amlogic gave you a crappy driver.
>> >
>> > Regards,
>> >
>> > Hans
>> >
>> >>
>> >> it looks like memcpy isn't cached or something but I don't know how to
>> >> identify problem
>> >> Any idea how to identify this problem.
>> >>
>> >> On Mon, Apr 8, 2013 at 2:46 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
>> >> > On Mon April 8 2013 14:42:32 Michal Lazo wrote:
>> >> >> Hi
>> >> >> 720x576 RGB 25, 30 fps and it take
>> >> >>
>> >> >> 25% cpu load on raspberry pi(ARM 700Mhz linux 3.6.11) or 8% on x86(AMD
>> >> >> 2GHz linux 3.2.0-39)
>> >> >>
>> >> >> it is simply too much
>> >> >
>> >> > No, that's what I would expect. Note that vivi was substantially improved recently
>> >> > when it comes to the image generation. That will be in the upcoming 3.9 kernel.
>> >> >
>> >> > This should reduce CPU load by quite a bit if memory serves.
>> >> >
>> >> > Regards,
>> >> >
>> >> > Hans
>> >> >
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> >> >> On Mon, Apr 8, 2013 at 9:42 AM, Peter Senna Tschudin
>> >> >> <peter.senna@xxxxxxxxx> wrote:
>> >> >> > Dear Michal,
>> >> >> >
>> >> >> > The CPU intensive part of the vivi driver is the image generation.
>> >> >> > This is not an issue for real drivers.
>> >> >> >
>> >> >> > Regards,
>> >> >> >
>> >> >> > Peter
>> >> >> >
>> >> >> > On Sun, Apr 7, 2013 at 9:32 PM, Michal Lazo <michal.lazo@xxxxxxxxxxx> wrote:
>> >> >> >> Hi
>> >> >> >> V4L2 driver vivi
>> >> >> >> generate 25% cpu load on raspberry pi(linux 3.6.11) or 8% on x86(linux 3.2.0-39)
>> >> >> >>
>> >> >> >> player
>> >> >> >> GST_DEBUG="*:3,v4l2src:3,v4l2:3" gst-launch-0.10 v4l2src
>> >> >> >> device="/dev/video0" norm=255 ! video/x-raw-rgb, width=720,
>> >> >> >> height=576, framerate=30000/1001 ! fakesink sync=false
>> >> >> >>
>> >> >> >> Anybody can answer me why?
>> >> >> >> And how can I do it better ?
>> >> >> >>
>> >> >> >> I use vivi as base example for my driver
>> >> >> >> --
>> >> >> >> To unsubscribe from this list: send the line "unsubscribe linux-media" in
>> >> >> >> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> >> >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > --
>> >> >> > Peter
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> >>
>> >>
>> >>
>> >>
>>
>>
>>
>>
--
Best Regards
Michal Lazo
Senior developer manager
mdragon.org
Slovakia
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