When changing VTs non-atomically the kernel works in conjunction with the Xserver in user space and receives the LUT information from the Xserver via a system call. When changing modes atomically for kdb, this information must be saved and restored without disturbing user space as if nothing ever happened.
There is a short cut used by this patch where gamma_store is used as the save space. If this turns out to be a problem in the future a pre-allocated chunk of memory will be required for each crtc to save and restore the LUT information.
Signed-off-by: Jason Wessel jason.wessel@windriver.com CC: Jesse Barnes jbarnes@virtuousgeek.org CC: David Airlie airlied@linux.ie CC: dri-devel@lists.freedesktop.org --- drivers/gpu/drm/drm_fb_helper.c | 26 ++++++++++++++++++++++++++ 1 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 625a2d5..8208e19 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -242,6 +242,30 @@ static int drm_fb_helper_parse_command_line(struct drm_fb_helper *fb_helper) return 0; }
+static void drm_fb_helper_save_lut_atomic(struct drm_crtc *crtc, struct drm_fb_helper *helper) +{ + uint16_t *r_base, *g_base, *b_base; + int i; + + r_base = crtc->gamma_store; + g_base = r_base + crtc->gamma_size; + b_base = g_base + crtc->gamma_size; + + for (i = 0; i < crtc->gamma_size; i++) + helper->funcs->gamma_get(crtc, &r_base[i], &g_base[i], &b_base[i], i); +} + +static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc) +{ + uint16_t *r_base, *g_base, *b_base; + + r_base = crtc->gamma_store; + g_base = r_base + crtc->gamma_size; + b_base = g_base + crtc->gamma_size; + + crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size); +} + int drm_fb_helper_debug_enter(struct fb_info *info) { struct drm_fb_helper *helper = info->par; @@ -260,6 +284,7 @@ int drm_fb_helper_debug_enter(struct fb_info *info) continue;
funcs = mode_set->crtc->helper_private; + drm_fb_helper_save_lut_atomic(mode_set->crtc, helper); funcs->mode_set_base_atomic(mode_set->crtc, mode_set->fb, mode_set->x, @@ -309,6 +334,7 @@ int drm_fb_helper_debug_leave(struct fb_info *info) continue; }
+ drm_fb_helper_restore_lut_atomic(mode_set->crtc); funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x, crtc->y, 0); }