> -----Original Message----- > From: Intel-xe <[email protected]> On Behalf Of Maarten > Lankhorst > Sent: Tuesday, July 21, 2026 7:56 PM > To: [email protected] > Cc: [email protected]; Maarten Lankhorst <[email protected]>; > Ville > Syrjälä <[email protected]> > Subject: [PATCH v2 5/5] drm/i915: Introduce intel_bo_fbdev_bios_fb_takeover() > > Pull the "do we want to use stolen for the BIOS FB?" checks into a new > intel_bo_fbdev_bios_fb_takeover() helper, and defer that decision until we're > ready > to reallocate the fbdev FB. This way even if we don't want to ultimately use > the > BIOS FB we'll keep the plane enabled until the replacement FB is ready. Should > hopefully result in fewer display blinks during boot. > > Additionally, on some platforms this allows us to re-create the framebuffer > when > stolen memory is not suitable, using the blitter engine to copy the contents > to > system memory without causing any flickering by not preserving the stolen > memory allocation. > > Based on a similar patch by Ville, that introduced > intel_bo_fbdev_bios_fb_ok().
Looks Good to me. Reviewed-by: Uma Shankar <[email protected]> Please get an ack from someone from Core KMD as well. @B S, Karthik Can we ask someone to check and give a Tested-by from validation side for this series. Regards, Uma Shankar > Cc: Ville Syrjälä <[email protected]> > Signed-off-by: Maarten Lankhorst <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_bo.c | 7 ++ > drivers/gpu/drm/i915/display/intel_bo.h | 1 + > drivers/gpu/drm/i915/display/intel_fbdev.c | 68 ++++++++++++++++--- > drivers/gpu/drm/i915/i915_bo.c | 14 +++- > drivers/gpu/drm/i915/i915_bo.h | 6 -- > drivers/gpu/drm/i915/i915_initial_plane.c | 14 ---- > drivers/gpu/drm/xe/display/xe_display_bo.c | 56 ++++++++++++++- > drivers/gpu/drm/xe/display/xe_display_bo.h | 6 -- > drivers/gpu/drm/xe/display/xe_initial_plane.c | 8 --- > include/drm/intel/display_parent_interface.h | 1 + > 10 files changed, 134 insertions(+), 47 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_bo.c > b/drivers/gpu/drm/i915/display/intel_bo.c > index 8ecdbb7e39f3d..878c62cb48b4f 100644 > --- a/drivers/gpu/drm/i915/display/intel_bo.c > +++ b/drivers/gpu/drm/i915/display/intel_bo.c > @@ -92,6 +92,13 @@ u32 intel_bo_fbdev_pitch_align(struct intel_display > *display, u32 stride) > return display->parent->bo->fbdev_pitch_align(stride); > } > > +struct drm_gem_object *intel_bo_fbdev_bios_fb_takeover(struct > +drm_gem_object *obj) { > + struct intel_display *display = to_intel_display(obj->dev); > + > + return display->parent->bo->fbdev_bios_fb_takeover(obj); > +} > + > struct drm_gem_object *intel_bo_fbdev_create(struct intel_display *display, > int > size) { > return display->parent->bo->fbdev_create(display->drm, size); diff --git > a/drivers/gpu/drm/i915/display/intel_bo.h > b/drivers/gpu/drm/i915/display/intel_bo.h > index 348f7fa669608..0410ee9c6d2e1 100644 > --- a/drivers/gpu/drm/i915/display/intel_bo.h > +++ b/drivers/gpu/drm/i915/display/intel_bo.h > @@ -34,6 +34,7 @@ struct drm_gem_object *intel_bo_framebuffer_lookup(struct > intel_display *display > const struct > drm_mode_fb_cmd2 *user_mode_cmd); > > u32 intel_bo_fbdev_pitch_align(struct intel_display *display, u32 stride); > +struct drm_gem_object *intel_bo_fbdev_bios_fb_takeover(struct > +drm_gem_object *obj); > struct drm_gem_object *intel_bo_fbdev_create(struct intel_display *display, > int > size); void intel_bo_fbdev_destroy(struct drm_gem_object *obj); int > intel_bo_fbdev_fill_info(struct drm_gem_object *obj, struct fb_info *info, > diff --git > a/drivers/gpu/drm/i915/display/intel_fbdev.c > b/drivers/gpu/drm/i915/display/intel_fbdev.c > index db0e36dd8722f..aac35b1ec0306 100644 > --- a/drivers/gpu/drm/i915/display/intel_fbdev.c > +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c > @@ -225,11 +225,11 @@ static void intel_fbdev_fill_mode_cmd(struct > intel_display *display, > > static struct intel_framebuffer * > __intel_fbdev_fb_alloc(struct intel_display *display, > - struct drm_fb_helper_surface_size *sizes) > + struct drm_fb_helper_surface_size *sizes, > + struct drm_gem_object *obj) > { > struct drm_mode_fb_cmd2 mode_cmd = {}; > struct drm_framebuffer *fb; > - struct drm_gem_object *obj; > int size; > > intel_fbdev_fill_mode_cmd(display, sizes, &mode_cmd); @@ -262,32 > +262,68 @@ __intel_fbdev_fb_alloc(struct intel_display *display, > > } > > -static bool bios_fb_ok(const struct intel_framebuffer *fb, > - const struct drm_fb_helper_surface_size *sizes) > +static struct intel_framebuffer * > +__intel_fbdev_fb_realloc(struct intel_display *display, > + const struct drm_framebuffer *orig_fb, > + struct drm_gem_object *obj) > +{ > + struct drm_framebuffer *new_fb; > + struct drm_mode_fb_cmd2 mode_cmd = { > + .flags = DRM_MODE_FB_MODIFIERS, > + .width = orig_fb->width, > + .height = orig_fb->height, > + .pitches[0] = orig_fb->pitches[0], > + .offsets[0] = orig_fb->offsets[0], > + .pixel_format = orig_fb->format->format, > + .modifier[0] = orig_fb->modifier, > + }; > + > + new_fb = intel_framebuffer_create(obj, orig_fb->format, &mode_cmd); > + > + if (IS_ERR(new_fb)) { > + intel_bo_fbdev_destroy(obj); > + return ERR_CAST(new_fb); > + } > + > + drm_gem_object_put(obj); > + return to_intel_framebuffer(new_fb); > +} > + > +static struct intel_framebuffer *bios_fb_pick(struct intel_framebuffer *fb, > + const struct > drm_fb_helper_surface_size *sizes) > { > struct intel_display *display = to_intel_display(fb->base.dev); > int width = fb->base.width; > int height = fb->base.height; > int depth = fb->base.format->depth; > int bpp = fb->base.format->cpp[0] * 8; > + struct drm_gem_object *new; > > if (sizes->fb_width > width || sizes->fb_height > height) { > drm_dbg_kms(display->drm, > "BIOS fb too small (%dx%d), we require (%dx%d), > releasing it\n", > width, height, sizes->fb_width, sizes->fb_height); > - return false; > + return NULL; > } > > if (sizes->surface_depth != depth || sizes->surface_bpp != bpp) { > drm_dbg_kms(display->drm, > "BIOS fb using wrong depth/bpp (%d/%d), we require > (%d/%d), releasing it\n", > depth, bpp, sizes->surface_depth, sizes- > >surface_bpp); > - return false; > + return NULL; > } > > - return true; > + new = intel_bo_fbdev_bios_fb_takeover(fb->base.obj[0]); > + if (IS_ERR(new)) > + return ERR_CAST(new); > + if (fb->base.obj[0] == new) > + return fb; > + > + /* Different object, re-create an intel_framebuffer around it */ > + return __intel_fbdev_fb_realloc(display, &fb->base, new); > } > > + > int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper, > struct drm_fb_helper_surface_size *sizes) { > @@ -305,9 +341,19 @@ int intel_fbdev_driver_fbdev_probe(struct drm_fb_helper > *helper, > > ifbdev->fb = NULL; > > - if (fb && !bios_fb_ok(fb, sizes)) { > - drm_framebuffer_put(&fb->base); > - fb = NULL; > + if (fb) { > + struct intel_framebuffer *bios_fb = > + bios_fb_pick(fb, sizes); > + > + if (IS_ERR(bios_fb)) { > + drm_dbg_kms(display->drm, "Re-using BIOS fb failed > (%pe).", bios_fb); > + bios_fb = NULL; > + } > + > + if (fb != bios_fb) { > + drm_framebuffer_put(&fb->base); > + fb = bios_fb; > + } > } > > wakeref = intel_display_rpm_get(display); @@ -316,7 +362,7 @@ int > intel_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper, > drm_dbg_kms(display->drm, > "no BIOS fb, allocating a new one\n"); > > - fb = __intel_fbdev_fb_alloc(display, sizes); > + fb = __intel_fbdev_fb_alloc(display, sizes, NULL); > if (IS_ERR(fb)) { > ret = PTR_ERR(fb); > goto out_unlock; > diff --git a/drivers/gpu/drm/i915/i915_bo.c b/drivers/gpu/drm/i915/i915_bo.c > index > 559341103ca7d..fe11c0be81013 100644 > --- a/drivers/gpu/drm/i915/i915_bo.c > +++ b/drivers/gpu/drm/i915/i915_bo.c > @@ -150,7 +150,7 @@ static u32 i915_bo_fbdev_pitch_align(u32 stride) > return ALIGN(stride, 64); > } > > -bool i915_bo_fbdev_prefer_stolen(struct drm_i915_private *i915, unsigned int > size) > +static bool i915_bo_fbdev_prefer_stolen(struct drm_i915_private *i915, > +unsigned int size) > { > /* Skip stolen on MTL as Wa_22018444074 mitigation. */ > if (IS_METEORLAKE(i915)) > @@ -164,6 +164,17 @@ bool i915_bo_fbdev_prefer_stolen(struct > drm_i915_private *i915, unsigned int siz > return i915->dsm.usable_size >= size * 2; } > > +static struct drm_gem_object *i915_bo_fbdev_bios_fb_takeover(struct > +drm_gem_object *obj) { > + struct drm_i915_private *i915 = to_i915(obj->dev); > + > + if (HAS_LMEM(i915) || > + i915_bo_fbdev_prefer_stolen(i915, obj->size)) > + return obj; > + > + return ERR_PTR(-EIO); > +} > + > static struct drm_gem_object *i915_bo_fbdev_create(struct drm_device *drm, > int > size) { > struct drm_i915_private *i915 = to_i915(drm); @@ -262,6 +273,7 @@ > const struct intel_display_bo_interface i915_display_bo_interface = { > .framebuffer_fini = i915_bo_framebuffer_fini, > .framebuffer_lookup = i915_bo_framebuffer_lookup, #if > IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) > + .fbdev_bios_fb_takeover = i915_bo_fbdev_bios_fb_takeover, > .fbdev_create = i915_bo_fbdev_create, > .fbdev_destroy = i915_bo_fbdev_destroy, > .fbdev_fill_info = i915_bo_fbdev_fill_info, diff --git > a/drivers/gpu/drm/i915/i915_bo.h b/drivers/gpu/drm/i915/i915_bo.h index > 39ba62696550e..57255d052dd9a 100644 > --- a/drivers/gpu/drm/i915/i915_bo.h > +++ b/drivers/gpu/drm/i915/i915_bo.h > @@ -4,12 +4,6 @@ > #ifndef __I915_BO_H__ > #define __I915_BO_H__ > > -#include <linux/types.h> > - > -struct drm_i915_private; > - > -bool i915_bo_fbdev_prefer_stolen(struct drm_i915_private *i915, unsigned int > size); > - > extern const struct intel_display_bo_interface i915_display_bo_interface; > > #endif /* __I915_BO_H__ */ > diff --git a/drivers/gpu/drm/i915/i915_initial_plane.c > b/drivers/gpu/drm/i915/i915_initial_plane.c > index 98858a78e46a3..d7792b65ec150 100644 > --- a/drivers/gpu/drm/i915/i915_initial_plane.c > +++ b/drivers/gpu/drm/i915/i915_initial_plane.c > @@ -12,7 +12,6 @@ > #include "gem/i915_gem_lmem.h" > #include "gem/i915_gem_region.h" > > -#include "i915_bo.h" > #include "i915_drv.h" > #include "i915_initial_plane.h" > > @@ -102,19 +101,6 @@ initial_plane_vma(struct drm_i915_private *i915, > mem->min_page_size); > size -= base; > > - /* > - * 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 > - * features. > - */ > - if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) && > - IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE) && > - mem == i915->mm.stolen_region && > - !i915_bo_fbdev_prefer_stolen(i915, size)) { > - drm_dbg_kms(&i915->drm, "Initial FB size exceeds half of stolen, > discarding\n"); > - return NULL; > - } > - > obj = i915_gem_object_create_region_at(mem, phys_base, size, > I915_BO_ALLOC_USER | > I915_BO_PREALLOC); > diff --git a/drivers/gpu/drm/xe/display/xe_display_bo.c > b/drivers/gpu/drm/xe/display/xe_display_bo.c > index d78d893210c4f..188796ae85933 100644 > --- a/drivers/gpu/drm/xe/display/xe_display_bo.c > +++ b/drivers/gpu/drm/xe/display/xe_display_bo.c > @@ -9,6 +9,7 @@ > #include "intel_fb.h" > #include "xe_bo.h" > #include "xe_display_bo.h" > +#include "xe_migrate.h" > #include "xe_pxp.h" > #include "xe_ttm_stolen_mgr.h" > #include "xe_wa.h" > @@ -120,7 +121,7 @@ static u32 xe_display_bo_fbdev_pitch_align(u32 stride) > return ALIGN(stride, XE_PAGE_SIZE); > } > > -bool xe_display_bo_fbdev_prefer_stolen(struct xe_device *xe, unsigned int > size) > +static bool xe_display_bo_fbdev_prefer_stolen(struct xe_device *xe, > +unsigned int size) > { > struct ttm_resource_manager *stolen; > > @@ -152,6 +153,58 @@ bool xe_display_bo_fbdev_prefer_stolen(struct > xe_device *xe, unsigned int size) > return stolen->size >= (size * 2) >> PAGE_SHIFT; } > > +static struct drm_gem_object > +*xe_display_bo_fbdev_bios_fb_takeover(struct drm_gem_object *obj) { > + struct xe_bo *orig_bo = gem_to_xe_bo(obj), *copy_bo; > + struct xe_device *xe = xe_bo_device(orig_bo); > + struct xe_validation_ctx ctx; > + struct drm_exec exec; > + int err; > + > + if (IS_DGFX(xe) || > + xe_display_bo_fbdev_prefer_stolen(xe, xe_bo_size(orig_bo))) > + return obj; > + > + copy_bo = xe_bo_create_pin_map_novm(xe, xe_device_get_root_tile(xe), > xe_bo_size(orig_bo), > + ttm_bo_type_kernel, > + XE_BO_FLAG_FORCE_WC | > XE_BO_FLAG_SYSTEM | XE_BO_FLAG_GGTT, > + false); > + if (IS_ERR(copy_bo)) > + return ERR_CAST(copy_bo); > + > + xe_validation_guard(&ctx, &xe->val, &exec, (struct xe_val_flags) {}, > err) { > + struct dma_fence *fence; > + > + drm_exec_lock_obj(&exec, &orig_bo->ttm.base); > + drm_exec_retry_on_contention(&exec); > + > + drm_exec_lock_obj(&exec, ©_bo->ttm.base); > + drm_exec_retry_on_contention(&exec); > + > + err = dma_resv_reserve_fences(orig_bo->ttm.base.resv, 1); > + if (err) > + break; > + > + err = dma_resv_reserve_fences(copy_bo->ttm.base.resv, 1); > + if (err) > + break; > + > + fence = xe_migrate_copy(xe_device_get_root_tile(xe)->migrate, > orig_bo, copy_bo, > + orig_bo->ttm.resource, copy_bo- > >ttm.resource, false); > + if (IS_ERR(fence)) { > + err = PTR_ERR(fence); > + break; > + } > + > + dma_resv_add_fence(copy_bo->ttm.base.resv, fence, > DMA_RESV_USAGE_KERNEL); > + dma_resv_add_fence(orig_bo->ttm.base.resv, fence, > DMA_RESV_USAGE_BOOKKEEP); > + return ©_bo->ttm.base; > + } > + > + xe_bo_unpin_map_no_vm(copy_bo); > + return ERR_PTR(err); > +} > + > static struct drm_gem_object *xe_display_bo_fbdev_create(struct drm_device > *drm, int size) { > struct xe_device *xe = to_xe_device(drm); @@ -214,6 +267,7 @@ const > struct intel_display_bo_interface xe_display_bo_interface = { > .framebuffer_fini = xe_display_bo_framebuffer_fini, > .framebuffer_lookup = xe_display_bo_framebuffer_lookup, #if > IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) > + .fbdev_bios_fb_takeover = xe_display_bo_fbdev_bios_fb_takeover, > .fbdev_create = xe_display_bo_fbdev_create, > .fbdev_destroy = xe_display_bo_fbdev_destroy, > .fbdev_fill_info = xe_display_bo_fbdev_fill_info, diff --git > a/drivers/gpu/drm/xe/display/xe_display_bo.h > b/drivers/gpu/drm/xe/display/xe_display_bo.h > index c72056884ff41..6879c104b0b1f 100644 > --- a/drivers/gpu/drm/xe/display/xe_display_bo.h > +++ b/drivers/gpu/drm/xe/display/xe_display_bo.h > @@ -4,12 +4,6 @@ > #ifndef __XE_DISPLAY_BO_H__ > #define __XE_DISPLAY_BO_H__ > > -#include <linux/types.h> > - > -struct xe_device; > - > -bool xe_display_bo_fbdev_prefer_stolen(struct xe_device *xe, unsigned int > size); > - > extern const struct intel_display_bo_interface xe_display_bo_interface; > > #endif > diff --git a/drivers/gpu/drm/xe/display/xe_initial_plane.c > b/drivers/gpu/drm/xe/display/xe_initial_plane.c > index 0f86b73036d03..8988c07e61934 100644 > --- a/drivers/gpu/drm/xe/display/xe_initial_plane.c > +++ b/drivers/gpu/drm/xe/display/xe_initial_plane.c > @@ -14,7 +14,6 @@ > #include "intel_display_types.h" > > #include "xe_bo.h" > -#include "xe_display_bo.h" > #include "xe_display_vma.h" > #include "xe_fb_pin.h" > #include "xe_ggtt.h" > @@ -102,13 +101,6 @@ initial_plane_bo(struct xe_device *xe, > > phys_base = base; > flags |= XE_BO_FLAG_STOLEN; > - > - if (IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE) && > - IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) && > - !xe_display_bo_fbdev_prefer_stolen(xe, plane_config->size)) > { > - drm_info(&xe->drm, "Initial FB size exceeds half of > stolen, > discarding\n"); > - return NULL; > - } > } > > bo = xe_bo_create_pin_map_at_novm(xe, tile0, size, phys_base, diff --git > a/include/drm/intel/display_parent_interface.h > b/include/drm/intel/display_parent_interface.h > index de395df9ca301..b218f8ecbe22a 100644 > --- a/include/drm/intel/display_parent_interface.h > +++ b/include/drm/intel/display_parent_interface.h > @@ -58,6 +58,7 @@ struct intel_display_bo_interface { > struct drm_file *filp, > const struct > drm_mode_fb_cmd2 *user_mode_cmd); #if > IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) > + struct drm_gem_object *(*fbdev_bios_fb_takeover)(struct > drm_gem_object > +*obj); > struct drm_gem_object *(*fbdev_create)(struct drm_device *drm, int > size); > void (*fbdev_destroy)(struct drm_gem_object *obj); > int (*fbdev_fill_info)(struct drm_gem_object *obj, struct fb_info > *info, struct > i915_vma *vma); > -- > 2.53.0
