Please use C style comments rather than C++.
Alex
From: Thomas Zimmermann
Sent: Wednesday, September 4, 2019 7:56 AM
To: dan...@ffwll.ch ; nor...@tronnes.org ;
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Cc: dri-devel@lists.freedesktop.org ; Thomas
Zimmermann ; Dave Airlie ; Greg
Kroah-Hartman ; Thomas Gleixner
; Gerd Hoffmann ; Deucher, Alexander
; Koenig, Christian ; Sam
Ravnborg ; Daniel Vetter ; Huang,
Ray ; Bartlomiej Zolnierkiewicz ;
Michał Mirosław ; Armijn Hemel
Subject: [PATCH v2 3/3] drm/mgag200: Map fbdev framebuffer while it's being
displayed
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
Fixes: 90f479ae51af ("drm/mgag200: Replace struct mga_fbdev with generic
framebuffer emulation")
Cc: Thomas Zimmermann
Cc: Noralf Trønnes
Cc: Dave Airlie
Cc: Greg Kroah-Hartman
Cc: Thomas Gleixner
Cc: Gerd Hoffmann
Cc: Alex Deucher
Cc: "Christian König"
Cc: Sam Ravnborg
Cc: Daniel Vetter
Cc: Huang Rui
Cc: Bartlomiej Zolnierkiewicz
Cc: "Michał Mirosław"
Cc: Armijn Hemel
Cc: Rong Chen
Cc: Feng Tang
Cc: Huang Ying
Cc: Davidlohr Bueso
---
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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