Re: [PATCH] drm/ast: Fix default resolution when no monitor is connected on DP

[Thomas Zimmermann]

Hi

Am 12.07.23 um 17:05 schrieb Sui Jingfeng:

Hi,


I'm here join to the discussion. Because I know a little about aspeed BMC.


On 2023/7/10 16:07, Jocelyn Falempe wrote:

On 07/07/2023 09:30, Thomas Zimmermann wrote:

Hi

Am 06.07.23 um 18:37 schrieb Jocelyn Falempe:
[...]

You could out-comment the VGA code in the ast driver for testing.

Oh, Thanks for the idea, I will try that.

The result is that I get a black screen on the remote BMC. So maybe adding a remote/bmc connector will solve that.

Could work. That would be a connector and encoder of type 'virtual'?

Not all ast devices have a BMC. Do you know how to detect its presence?

Hum, I though all ast devices have a BMC,

No, Thomas is right, not all ast devices have a BMC.

I have two discrete AST BMC cards, see [1] for reference.

I generally using the ast2400 BMC cards to testing patches and study drm/ast driver. It seems that this two cards are pure 2D display card, because they don't have a net interface(can not plug-in the net cable). [1] https://github.com/loongson-gfx/loongson_boards/blob/main/ast_bmc_cards/ast1400_and_ast2400.jpg

Thanks for the info.

Best regards
Thomas

and I don't see a way to detect that BMC is active or present.

I think we better find one, then if the BMC is active (present).

we could create a virtual encoder and connector safely.

(It would be even better to know the browser's size, and automatically resize, like when using a VM. But I'm not sure the hardware/firmware is able to do this).

(a scratch register) or something like that.

But this really need you have the firmware (source code) to support this.

Or you are luckily, if there somebody already done this for you.

I think it is not difficult, it just that need the firmware of your board to set a value to a register,

On the other hand, are there any drawback to present a BMC connector even when the hardware doesn't have it ?

If not properly setting up, I think you will create two encoder and two connector in the system.

Best regards
Thomas

Best regards,

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

OpenPGP_signature
Description: OpenPGP digital signature