Hi,
Am 01.10.25 um 22:50 schrieb Melissa Wen:
On 26/09/2025 07:36, Stefan Wahren wrote:
Hi Marek,
....
AFAIK the offending clock change isn't in the downstream kernel, so I
like to see the opinion of María and the Raspberry Pi people first.
Hi,
I see in the downstream kernel the CLOCK_V3D was removed in favor of
firmware clock:
https://github.com/raspberrypi/linux/blob/rpi-6.12.y/drivers/clk/bcm/clk-bcm2835.c#L2076
Also, v3d in RPi4 is set to use the firmware clock:
https://github.com/torvalds/linux/blob/master/arch/arm/boot/dts/broadcom/bcm2711-rpi.dtsi#L97
I think v3d clock is missed on boot, but I also think the issue should
be solved by setting the v3d firmware clock for Pi3.
WDYT? Can you check it on your side? Something like:
diff --git a/arch/arm/boot/dts/broadcom/bcm2835-rpi-common.dtsi
b/arch/arm/boot/dts/broadcom/bcm2835-rpi-common.dtsi
index 8b3c21d9f333..3289cb5dfa8e 100644
--- a/arch/arm/boot/dts/broadcom/bcm2835-rpi-common.dtsi
+++ b/arch/arm/boot/dts/broadcom/bcm2835-rpi-common.dtsi
@@ -14,6 +14,7 @@ &hdmi {
};
&v3d {
+ clocks = <&firmware_clocks 5>;
power-domains = <&power RPI_POWER_DOMAIN_V3D>;
};
thanks for pointing out. Handling the same clock by clk-raspberrypi and
clk-bcm2835 is a very bad idea. But it looks like that's not the only
affected clock. I see at least ISP and VEC, which might be affected.
Does anyone know, if the clk-raspberrypi always use a matching clock
name in comparison to the clk-bcm2835?
clk-bcm2835 - clk-raspberrypi
BCM2835_CLOCK_V3D equals to RPI_FIRMWARE_V3D_CLK_ID
BCM2835_CLOCK_ISP equals to RPI_FIRMWARE_ISP_CLK_ID
...
Or are there any clocks, which have different names in both drivers but
describe the same hardware clock?
Best regards
Best regards,
Melissa
Currently I know that in the error case the following clocks are
disabled during boot of Raspberry Pi 3B+:
fw-clk-vec
fw-clk-isp
fw-clk-v3d
So it's very likely that the vc4 drivers tries to access the register
after the these clocks has been disabled and then the system freeze.
The workaround above was just a wild guess, so currently I don't know
why this change avoid the freeze.
Best regards
