[PATCH] ARM: dts: bcm2835: Enable 3D rendering through V3D

[Phil Elwell]

Hello all,

On Fri, 12 Apr 2024 at 18:17, Stefan Wahren <wahrenst at gmx.net> wrote:
>
> Hi Maíra,
>
> [add Phil & Dave]
>
> Am 12.04.24 um 15:25 schrieb Maíra Canal:
> > RPi 0-3 is packed with a GPU that provides 3D rendering capabilities to
> > the RPi. Currently, the downstream kernel uses an overlay to enable the
> > GPU and use GPU hardware acceleration. When deploying a mainline kernel
> > to the RPi 0-3, we end up without any GPU hardware acceleration
> > (essentially, we can't use the OpenGL driver).
> >
> > Therefore, enable the V3D core for the RPi 0-3 in the mainline kernel.
> thanks for trying to improve the combination Raspberry Pi OS + Mainline
> Kernel. I think i'm able to reproduce the issue with Raspberry Pi 3 B +
> on Buster.

Buster? We launched Buster with 4.19 and ended on 5.10. We've moved
onto Bookworm now. A lot has changed in that time...

> From the kernel side everything looks good:
>
> [   11.054833] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4])
> [   11.055118] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4])
> [   11.055340] vc4-drm soc:gpu: bound 3f004000.txp (ops vc4_txp_ops [vc4])
> [   11.055521] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops
> vc4_crtc_ops [vc4])
> [   11.055695] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops
> vc4_crtc_ops [vc4])
> [   11.055874] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops
> vc4_crtc_ops [vc4])
> [   11.056020] vc4-drm soc:gpu: bound 3fc00000.v3d (ops vc4_v3d_ops [vc4])
> [   11.063277] Bluetooth: hci0: BCM4345C0
> 'brcm/BCM4345C0.raspberrypi,3-model-b-plus.hcd' Patch
> [   11.070466] [drm] Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
> [   11.174803] Console: switching to colour frame buffer device 240x75
> [   11.205125] vc4-drm soc:gpu: [drm] fb0: vc4drmfb frame buffer device
>
> But in Raspberry Pi OS there is a systemd script which is trying to
> check for the V3D driver /usr/lib/systemd/scripts/gldriver_test.sh
> Within the first check "raspi-config nonint is_kms" is called, which
> always seems to fail. If i run strace on this command it seems to check
> for /proc/device-tree/soc/v3d at 7ec00000/status which doesn't exists in
> the Mainline device tree.
>
> Maybe there is a chance to improve the userspace tool?

...such as the raspi-config tool, which now always succeeds for is_kms.

Phil

> >
> > Signed-off-by: Maíra Canal <mcanal at igalia.com>
> > ---
> >
> > I decided to add the status property to the `bcm2835-common.dtsi`, but
> > there are two other options:
> >
> > 1. To add the status property to the `bcm2835-rpi-common.dtsi` file
> > 2. To add the status property to each individual RPi model, e.g.
> > `bcm2837-rpi-3-b.dts`.
> >
> > Let me know which option is more suitable, and if `bcm2835-common.dtsi`
> > is not the best option, I can send a v2.
> >
> > Best Regards,
> > - Maíra
> >
> >   arch/arm/boot/dts/broadcom/bcm2835-common.dtsi | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm/boot/dts/broadcom/bcm2835-common.dtsi b/arch/arm/boot/dts/broadcom/bcm2835-common.dtsi
> > index 9261b67dbee1..851a6bce1939 100644
> > --- a/arch/arm/boot/dts/broadcom/bcm2835-common.dtsi
> > +++ b/arch/arm/boot/dts/broadcom/bcm2835-common.dtsi
> > @@ -139,6 +139,7 @@ v3d: v3d at 7ec00000 {
> >                       compatible = "brcm,bcm2835-v3d";
> >                       reg = <0x7ec00000 0x1000>;
> >                       interrupts = <1 10>;
> > +                     status = "okay";
> >               };
> >
> >               vc4: gpu {
>