Re: [RFC PATCH 3/9] drm/rockchip: Convert to support atomic API

On 2015年12月01日 16:18, Daniel Stone wrote:

Hi Mark,

On 1 December 2015 at 03:26, Mark Yaomark.yao@rock-chips.com wrote:

...

...

+static void rockchip_atomic_wait_for_complete(struct drm_atomic_state *state) +{

•   struct drm_crtc_state *crtc_state;
  

•   struct drm_crtc *crtc;
  

•   int i;
  

•   for_each_crtc_in_state(state, crtc, crtc_state, i) {
  

•           if (!crtc->state->active)
  

•                   continue;
  

•           WARN_ON(drm_crtc_vblank_get(crtc));
  

•   }
  

•   for_each_crtc_in_state(state, crtc, crtc_state, i) {
  

•           if (!crtc->state->active)
  

•                   continue;
  

•           rockchip_crtc_wait_for_update(crtc);
  

•   }
  

I'd be much more comfortable if this passed in an explicit pointer to state, or an address to wait for, rather than have wait_for_complete dig out state with no locking. The latter is potentially racy for async operations.

Hi Daniel "if this passed in an explicit pointer to state, or an address to wait for", I don't understand, can you point how it work?