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 <[email protected]>
Fixes: 90f479ae51af ("drm/mgag200: Replace struct mga_fbdev with generic
framebuffer emulation")
Cc: Thomas Zimmermann <[email protected]>
Cc: Noralf Trønnes <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Gerd Hoffmann <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: "Christian König" <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Huang Rui <[email protected]>
Cc: Bartlomiej Zolnierkiewicz <[email protected]>
Cc: "Michał Mirosław" <[email protected]>
Cc: Armijn Hemel <[email protected]>
Cc: Rong Chen <[email protected]>
Cc: Feng Tang <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
---
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;
--
2.23.0
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