[PATCH v3 4/7] bcm2835: brcm,bcm2708-fb device is using r5g6b5 format

[Stefan Wahren]

Hi Ivan,

Am 19.12.23 um 09:51 schrieb Ivan T. Ivanov:
> On 12-18 23:32, Stefan Wahren wrote:
>>>    static const struct udevice_id bcm2835_video_ids[] = {
>>> -	{ .compatible = "brcm,bcm2835-hdmi" },
>>> -	{ .compatible = "brcm,bcm2711-hdmi0" },
>>> -	{ .compatible = "brcm,bcm2708-fb" },
>>> +	{ .compatible = "brcm,bcm2835-hdmi",  .data = VIDEO_BPP32},
>>> +	{ .compatible = "brcm,bcm2711-hdmi0", .data = VIDEO_BPP32},
>>> +	{ .compatible = "brcm,bcm2708-fb",    .data = VIDEO_BPP16 },
>> this change looks wrong to me. Before we used VIDEO_BPP32 for
>> brcm,bcm2708-fb. I think it's hard to explain why we should downgrade
>> the other boards. I would expect some brcm,bcm2712 compatible at least
>> this needs an explanation in the commit message.
>>
> If you are confident that this semi device was working before with
> BPP32 I will try to find better way to handle this. Do you remember
> which RPi version was this?
as said before i'm don't have much experience with U-Boot, so i'm not
confident. But downgrading the bpp value for an existing setting only to
make RPi 5 work, isn't a good approach. It's a hack.

A quick search for the compatible revealed this [1], so it looks like a
fallback which applies to all Raspberry Pi boards with a firmware
provided DTB.

In case all of them uses 16 bit, i'm fine with this change but then the
commit log should mention this. I think these are points which needs to
be discussed with the Raspberry Pi guys.

Best regards

[1] - https://lists.denx.de/pipermail/u-boot/2018-July/333476.html
>
> Thanks,
> Ivan
>