Re: [PATCH 0/6] staging: BCM2835 MMAL V4L2 camera driver

[Eric Anholt]

Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> writes:

> Em Wed, 15 Mar 2017 18:46:24 -0700
> Michael Zoran <mzoran@xxxxxxxxxxxx> escreveu:
>
>> On Wed, 2017-03-15 at 22:08 -0300, Mauro Carvalho Chehab wrote:
>> 
>> > No, I didn't. Thanks! Applied it but, unfortunately, didn't work.
>> > Perhaps I'm missing some other patch. I'm compiling it from
>> > the Greg's staging tree (branch staging-next):
>> > 	https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.
>> > git/log/?h=staging-next
>> > 
>> > Btw, as I'm running Raspbian, and didn't want to use compat32 bits,Â
>> > I'm compiling the Kernel as an arm32 bits Kernel.
>> > 
>> > I did a small trick to build the DTB on arm32:
>> > 
>> > 	ln -sf ../../../arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts
>> > arch/arm/boot/dts/bcm2837-rpi-3-b.dts
>> > 	ln -sf ../../../arm64/boot/dts/broadcom/bcm2837.dtsi
>> > arch/arm/boot/dts/bcm2837.dtsi
>> > 	git checkout arch/arm/boot/dts/Makefile
>> > 	sed "s,bcm2835-rpi-zero.dtb,bcm2835-rpi-zero.dtb bcm2837-rpi-3-
>> > b.dtb," a && mv a arch/arm/boot/dts/Makefile
>> >   
>> 
>> Two other hacks are currently needed to get the camera to work:
>> 
>> 1. Add this to config.txt(This required to get the firmware to detect
>> the camera)
>> 
>> start_x=1
>> gpu_mem=128
>
> I had this already.
>
>> 
>> 2. VC4 is incompatible with the firmware at this time, so you need 
>> to presently munge the build configuration. What you do is leave
>> simplefb in the build config(I'm assuming you already have that), but
>> you will need to remove VC4 from the config.
>> 
>> The firmware currently adds a node for a simplefb for debugging
>> purposes to show the boot log.  Surprisingly, this is still good enough
>> for basic usage and testing.  
>
> That solved the issue. Thanks! It would be good to add a notice
> about that at the TODO, not let it build if DRM_VC4.
>
> Please consider applying the enclosed path.

The VC4 incompatibility (camera firmware's AWB ends up briefly using the
GPU, without coordinating with the Linux driver) is supposed to be fixed
in current firmware
(https://github.com/raspberrypi/firmware/issues/760#issuecomment-287391025)

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