The generic fbdev emulation will map and unmap the framebuffer's memory if required. As consoles are most often updated while being on screen, we map the fbdev buffer while it's being displayed. This avoids frequent map/unmap operations in the fbdev code. The original fbdev code in mgag200 used the same trick to improve performance.
v2: * fix typo in comment
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Fixes: 90f479ae51af ("drm/mgag200: Replace struct mga_fbdev with generic framebuffer emulation") Cc: Thomas Zimmermann tzimmermann@suse.de Cc: Noralf Trønnes noralf@tronnes.org Cc: Dave Airlie airlied@redhat.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Gerd Hoffmann kraxel@redhat.com Cc: Alex Deucher alexander.deucher@amd.com Cc: "Christian König" christian.koenig@amd.com Cc: Sam Ravnborg sam@ravnborg.org Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Huang Rui ray.huang@amd.com Cc: Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com Cc: "Michał Mirosław" mirq-linux@rere.qmqm.pl Cc: Armijn Hemel armijn@tjaldur.nl Cc: Rong Chen rong.a.chen@intel.com Cc: Feng Tang feng.tang@intel.com Cc: Huang Ying ying.huang@intel.com Cc: Davidlohr Bueso dave@stgolabs.net --- drivers/gpu/drm/mgag200/mgag200_mode.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c index 5e778b5f1a10..7b95c59341f5 100644 --- a/drivers/gpu/drm/mgag200/mgag200_mode.c +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c @@ -860,13 +860,20 @@ static int mga_crtc_do_set_base(struct drm_crtc *crtc, struct drm_framebuffer *fb, int x, int y, int atomic) { + struct drm_fb_helper *fb_helper = crtc->dev->fb_helper; struct drm_gem_vram_object *gbo; int ret; s64 gpu_addr; + void *base;
if (!atomic && fb) { gbo = drm_gem_vram_of_gem(fb->obj[0]); drm_gem_vram_unpin(gbo); + + // Unmap fbdev FB if it's not being displayed + // any longer. + if (fb == fb_helper->buffer->fb) + drm_gem_vram_kunmap(gbo); }
gbo = drm_gem_vram_of_gem(crtc->primary->fb->obj[0]); @@ -882,6 +889,14 @@ static int mga_crtc_do_set_base(struct drm_crtc *crtc,
mga_set_start_address(crtc, (u32)gpu_addr);
+ // Map fbdev FB while it's being displayed. This avoids frequent + // mapping and unmapping within the fbdev code. + if (crtc->primary->fb == fb_helper->buffer->fb) { + base = drm_gem_vram_kmap(gbo, true, NULL); + if (IS_ERR(base)) + DRM_ERROR("failed to kmap fbcon\n"); + } + return 0;
err_drm_gem_vram_unpin: @@ -1403,9 +1418,14 @@ static void mga_crtc_disable(struct drm_crtc *crtc) DRM_DEBUG_KMS("\n"); mga_crtc_dpms(crtc, DRM_MODE_DPMS_OFF); if (crtc->primary->fb) { + struct drm_fb_helper *fb_helper = crtc->dev->fb_helper; struct drm_framebuffer *fb = crtc->primary->fb; struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(fb->obj[0]); + + // Unmap if it's the fbdev FB. + if (fb == fb_helper->buffer->fb) + drm_gem_vram_kunmap(gbo); drm_gem_vram_unpin(gbo); } crtc->primary->fb = NULL;