[v4] drm/xe/fbdev: Limit the usage of stolen for LNL+

[Shankar, Uma]

> -----Original Message-----
> From: Shankar, Uma <uma.shankar at intel.com>
> Sent: Wednesday, July 17, 2024 1:53 PM
> To: intel-gfx at lists.freedesktop.org; intel-xe at lists.freedesktop.org
> Cc: ville.syrjala at linux.intel.com; Ceraolo Spurio, Daniele
> <daniele.ceraolospurio at intel.com>; Belgaumkar, Vinay
> <vinay.belgaumkar at intel.com>; Roper, Matthew D
> <matthew.d.roper at intel.com>; De Marchi, Lucas <lucas.demarchi at intel.com>;
> Shankar, Uma <uma.shankar at intel.com>
> Subject: [v4] drm/xe/fbdev: Limit the usage of stolen for LNL+
> 
> As per recommendation in the workarounds:
> WA_22019338487
> 
> There is an issue with accessing Stolen memory pages due a hardware limitation.
> Limit the usage of stolen memory for fbdev for LNL+. Don't use BIOS FB from
> stolen on LNL+ and assign the same from system memory.
> 
> v2: Corrected the WA Number, limited WA to LNL and
>     Adopted XE_WA framework as suggested by Lucas and Matt.
> 
> v3: Introduced the waxxx_display to implement display side
>     of WA changes on Lunarlake. Used xe_root_mmio_gt and
>     avoid the for loop (Suggested by Lucas)
> 
> v4: Fixed some nits (Luca)

Pushed the change to drm-xe-next. Thanks for the reviews and suggestions.

Regards,
Uma Shankar

> Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>
> ---
>  drivers/gpu/drm/xe/display/intel_fbdev_fb.c   | 6 +++++-
>  drivers/gpu/drm/xe/display/xe_plane_initial.c | 6 ++++++
>  drivers/gpu/drm/xe/xe_wa_oob.rules            | 1 +
>  3 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
> b/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
> index 816ad13821a8..cd8948c08661 100644
> --- a/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
> +++ b/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
> @@ -10,6 +10,9 @@
>  #include "xe_bo.h"
>  #include "xe_gt.h"
>  #include "xe_ttm_stolen_mgr.h"
> +#include "xe_wa.h"
> +
> +#include <generated/xe_wa_oob.h>
> 
>  struct intel_framebuffer *intel_fbdev_fb_alloc(struct drm_fb_helper *helper,
>  					       struct drm_fb_helper_surface_size
> *sizes) @@ -37,7 +40,7 @@ struct intel_framebuffer
> *intel_fbdev_fb_alloc(struct drm_fb_helper *helper,
>  	size = PAGE_ALIGN(size);
>  	obj = ERR_PTR(-ENODEV);
> 
> -	if (!IS_DGFX(xe)) {
> +	if (!IS_DGFX(xe) && !XE_WA(xe_root_mmio_gt(xe),
> 22019338487_display))
> +{
>  		obj = xe_bo_create_pin_map(xe, xe_device_get_root_tile(xe),
>  					   NULL, size,
>  					   ttm_bo_type_kernel,
> XE_BO_FLAG_SCANOUT | @@ -48,6 +51,7 @@ struct intel_framebuffer
> *intel_fbdev_fb_alloc(struct drm_fb_helper *helper,
>  		else
>  			drm_info(&xe->drm, "Allocated fbdev into stolen failed:
> %li\n", PTR_ERR(obj));
>  	}
> +
>  	if (IS_ERR(obj)) {
>  		obj = xe_bo_create_pin_map(xe, xe_device_get_root_tile(xe),
> NULL, size,
>  					   ttm_bo_type_kernel,
> XE_BO_FLAG_SCANOUT | diff --git
> a/drivers/gpu/drm/xe/display/xe_plane_initial.c
> b/drivers/gpu/drm/xe/display/xe_plane_initial.c
> index 5eccd6abb3ef..a50ab9eae40a 100644
> --- a/drivers/gpu/drm/xe/display/xe_plane_initial.c
> +++ b/drivers/gpu/drm/xe/display/xe_plane_initial.c
> @@ -18,6 +18,9 @@
>  #include "intel_frontbuffer.h"
>  #include "intel_plane_initial.h"
>  #include "xe_bo.h"
> +#include "xe_wa.h"
> +
> +#include <generated/xe_wa_oob.h>
> 
>  static bool
>  intel_reuse_initial_plane_obj(struct intel_crtc *this, @@ -104,6 +107,9 @@
> initial_plane_bo(struct xe_device *xe,
>  		phys_base = base;
>  		flags |= XE_BO_FLAG_STOLEN;
> 
> +		if (XE_WA(xe_root_mmio_gt(xe), 22019338487_display))
> +			return NULL;
> +
>  		/*
>  		 * If the FB is too big, just don't use it since fbdev is not very
>  		 * important and we should probably use that space with FBC or
> other diff --git a/drivers/gpu/drm/xe/xe_wa_oob.rules
> b/drivers/gpu/drm/xe/xe_wa_oob.rules
> index 08f7336881e3..540d38603f32 100644
> --- a/drivers/gpu/drm/xe/xe_wa_oob.rules
> +++ b/drivers/gpu/drm/xe/xe_wa_oob.rules
> @@ -29,4 +29,5 @@
>  13011645652	GRAPHICS_VERSION(2004)
>  22019338487	MEDIA_VERSION(2000)
>  		GRAPHICS_VERSION(2001)
> +22019338487_display	PLATFORM(LUNARLAKE)
>  16023588340	GRAPHICS_VERSION(2001)
> --
> 2.42.0