[BUG] The bottom and right edges on the tty are not shown on Apple T2 MacBooks with Retina display

[Aditya Garg]

Hello maintainers

This bug has been there for a long time, and hasn't been fixed yet. In case the Intel GPU is used as boot GPU on Apple T2 MacBooks, the bottom and right edges of the tty are no longer seen, thus making some text not visible.

It has been reported in almost all Apple T2 MacBooks with Intel GPU, which have the Retina display.

In case of a dual GPU MacBook, if the AMD dGPU is used to boot, the bug no longer exists.

This patch below was submitted 3 years ago, and it fixes this issue.

> On 11 Jan 2022, at 1:25 PM, Ashish Arora <ashisharora.linux at outlook.com> wrote:
> 
> From: Ashish Arora <ashisharora.linux at outlook.com>
> 
> On certain 4k panels and Macs, the BIOS framebuffer is larger than what
> panel requires causing display corruption. Introduce a check for the same.
> 
> 
> Signed-off-by: Ashish Arora <ashisharora.linux at outlook.com>
> Reviewed-by: Aun-Ali Zaidi <admin at kodeit.net>
> ---
> V2 :- Use != instead of < and >
> V3 :- Mention Macs (Thanks to Orlando)
> drivers/gpu/drm/i915/display/intel_fbdev.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> index 842c04e63..16b1c82b2 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> @@ -181,10 +181,10 @@ static int intelfb_create(struct drm_fb_helper *helper,
> int ret;
> 
> if (intel_fb &&
> -    (sizes->fb_width > intel_fb->base.width ||
> -     sizes->fb_height > intel_fb->base.height)) {
> +    (sizes->fb_width != intel_fb->base.width ||
> +     sizes->fb_height != intel_fb->base.height)) {
> drm_dbg_kms(&dev_priv->drm,
> -    "BIOS fb too small (%dx%d), we require (%dx%d),"
> +    "BIOS fb not valid (%dx%d), we require (%dx%d),"
>    " releasing it\n",
>    intel_fb->base.width, intel_fb->base.height,
>    sizes->fb_width, sizes->fb_height);
> -- 
> 2.25.1
> 
> 
>