[PATCH] light weight drm fbdev panning

[Dave Airlie]

On Tue, Aug 3, 2010 at 8:01 AM, James Simmons <jsimmons at infradead.org> wrote:
>
> 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.

Dave.

>
> Signed-By: James Simmons <jsimmons at 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 at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>