...

This patch uses the much lighter mode_set_base instead of calling a full mode set. Tested on a i915 netbook. Patch should be against drm-core-next.

The kms code should always fallback if appropriate, I've definitely seen some modesets I thought were triggered by the pan_display codepath, so I'd expect if we add this, we might some base sets at the wrong time. Unless we can prove we only get pan_displays when expected.

fb_pan_display is called from two places. One is from a userland application. The second is the framebuffer console layer when in VT mode. Currently in order for the console layer to actually using panning the sruct fb_info flag field must be set with FBINFO_HWACCEL_XPAN and/or FBINFO_HWACCEL_YPAN. Currently no KMS driver set this field. I actually did to try it. Currently fbcon uses the flag in struct fb_info to determine the most optimized path to scroll/draw etc. If pan_display fails the fbcon code adapts to that change.

...

Signed-By: James Simmons jsimmons@infradead.org

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 7196620..99889e3 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -730,15 +730,20 @@ int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,                              struct fb_info *info)  {        struct drm_fb_helper *fb_helper = info->par;

• struct drm_crtc_helper_funcs *crtc_funcs;

struct drm_device *dev = fb_helper->dev;        struct drm_mode_set *modeset;        struct drm_crtc *crtc;

• int ret = 0;

• int ret = -ENXIO;

int i;

mutex_lock(&dev->mode_config.mutex);        for (i = 0; i < fb_helper->crtc_count; i++) {                crtc = fb_helper->crtc_info[i].mode_set.crtc;

• crtc_funcs = crtc->helper_private;
• if (!crtc_funcs->mode_set_base)
• continue;

modeset = &fb_helper->crtc_info[i].mode_set;

@@ -746,7 +751,8 @@ int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,                modeset->y = var->yoffset;

if (modeset->num_connectors) {

• ret = crtc->funcs->set_config(modeset);

• ret = crtc_funcs->mode_set_base(crtc, modeset->x,
• modeset->y, crtc->fb);

if (!ret) {                                info->var.xoffset = var->xoffset;                                info->var.yoffset = var->yoffset; _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel