Re: [PATCH v3 2/4] drm: Add support for ARM's HDLCD controller.

Hi Liviu,

On 2 December 2015 at 12:23, Liviu Dudau Liviu.Dudau@arm.com wrote:

•   if (irq_status & HDLCD_INTERRUPT_VSYNC) {
  

•           unsigned long flags;
  

•           drm_handle_vblank(drm, 0);
  

•           spin_lock_irqsave(&drm->event_lock, flags);
  

•           if (hdlcd->event) {
  

•                   drm_send_vblank_event(drm, hdlcd->event->pipe, hdlcd->event);
  

•                   drm_crtc_vblank_put(&hdlcd->crtc);
  

•                   hdlcd->event = NULL;
  

•           }
  

•           spin_unlock_irqrestore(&drm->event_lock, flags);
  

•   }
  

As with VC4 and Rockchip, you're missing a ->preclose handler in your drm_drv, to make sure that you don't try to send events to a dead client (which causes an OOPS): https://git.collabora.com/cgit/user/daniels/linux.git/commit/?h=wip/4.4.x/ro... (and its parent)

Also, is there anything preventing clients from submitting multiple pageflips before the event is sent? I couldn't see anything from a quick look, so you could have the situation of: - client submits pageflip, event 1 stored to hdlcd->event - client submits pageflip, event 2 stored to hdlcd->event - vblank arrives, event 2 is sent - event 1 has disappeared and been leaked

Cheers, Daniel