Hello Ard and Huacai,
On 5/20/22 11:17, Ard Biesheuvel wrote:
[snip]
>> +
>> +static int __init register_gop_device(void)
>> +{
>> + void *pd;
>> +
>> + if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
>> + return 0;
>> + pd = platform_device_register_data(NULL, "efi-framebuffer", 0,
>> + &screen_info, sizeof(screen_info));
>> + return PTR_ERR_OR_ZERO(pd);
>> +}
>> +subsys_initcall(register_gop_device);
>
> Not sure this is now the correct way to do this - cc'ing Javier.
>
Is not the correct way to do it indeed, that can just be dropped.
We have unified now all the system framebuffer platform device
registration under drivers/firmware/sysfb.c (and the EFI quirks
if needed under drivers/firmware/efi/sysfb_efi.c).
So the only thing that a platform should do, is to enable the
the CONFIG_SYSFB config option. The screen_info should be set
correctly from the EFI GOP, but it seems that's already working
since you were already using it in register_gop_device().
But also, the "efi-framebuffer" platform device matches against
the legacy efifb fbdev driver. And now there's a simpledrm driver
that is also able to use the firmware-provided framebuffer.
You can enable that driver with CONFIG_DRM_SIMPLEDRM.
That driver though doesn't match against "efi-framebuffer" but with
a "simple-framebuffer", to make sysfb register that instead of the
"efi-framebuffer" device, you need to set CONFIG_SYSFB_SIMPLEFB too.
If for some reasons you need to provide a fbdev interface to the
user-space, you can enable CONFIG_DRM_FBDEV_EMULATION to have that.
In summary, just enable the following to use the firmware framebuffer:
CONFIG_DRM_SIMPLEDRM=y
CONFIG_DRM_FBDEV_EMULATION=y
CONFIG_SYSFB=y
CONFIG_SYSFB_SIMPLEFB=y
--
Best regards,
Javier Martinez Canillas
Linux Engineering
Red Hat
