[Mesa-dev] [PATCH] vulkan/wsi/x11: handle timeouts properly in next image acquire

[Edward O'Callaghan]

Reviewed-by: Edward O'Callaghan <funfunctor at folklore1984.net>

On 10/26/2016 01:23 PM, Dave Airlie wrote:
> From: Dave Airlie <airlied at redhat.com>
> 
> For 0 timeout, just poll for an event, and if none, return
> For UINT64_MAX timeout, just wait for special event blocked
> For other timeouts get the xcb fd and block on it, decreasing
> the timeout if we get woken up for non-special events.
> 
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> ---
>  src/vulkan/wsi/wsi_common_x11.c | 58 +++++++++++++++++++++++++++++++++++++----
>  1 file changed, 53 insertions(+), 5 deletions(-)
> 
> diff --git a/src/vulkan/wsi/wsi_common_x11.c b/src/vulkan/wsi/wsi_common_x11.c
> index b5832c6..2ed47b0 100644
> --- a/src/vulkan/wsi/wsi_common_x11.c
> +++ b/src/vulkan/wsi/wsi_common_x11.c
> @@ -34,6 +34,7 @@
>  #include <errno.h>
>  #include <string.h>
>  
> +#include <poll.h>
>  #include "util/hash_table.h"
>  
>  #include "wsi_common.h"
> @@ -538,6 +539,26 @@ x11_handle_dri3_present_event(struct x11_swapchain *chain,
>     return VK_SUCCESS;
>  }
>  
> +
> +static uint64_t wsi_get_current_time(void)
> +{
> +   uint64_t current_time;
> +   struct timespec tv;
> +
> +   clock_gettime(CLOCK_MONOTONIC, &tv);
> +   current_time = tv.tv_nsec + tv.tv_sec*1000000000ull;
> +   return current_time;
> +}
> +
> +static uint64_t wsi_get_absolute_timeout(uint64_t timeout)
> +{
> +   uint64_t current_time = wsi_get_current_time();
> +
> +   timeout = MIN2(UINT64_MAX - current_time, timeout);
> +
> +   return current_time + timeout;
> +}
> +
>  static VkResult
>  x11_acquire_next_image(struct wsi_swapchain *anv_chain,
>                         uint64_t timeout,
> @@ -545,7 +566,9 @@ x11_acquire_next_image(struct wsi_swapchain *anv_chain,
>                         uint32_t *image_index)
>  {
>     struct x11_swapchain *chain = (struct x11_swapchain *)anv_chain;
> -
> +   xcb_generic_event_t *event;
> +   struct pollfd pfds;
> +   uint64_t atimeout;
>     while (1) {
>        for (uint32_t i = 0; i < chain->image_count; i++) {
>           if (!chain->images[i].busy) {
> @@ -558,10 +581,35 @@ x11_acquire_next_image(struct wsi_swapchain *anv_chain,
>        }
>  
>        xcb_flush(chain->conn);
> -      xcb_generic_event_t *event =
> -         xcb_wait_for_special_event(chain->conn, chain->special_event);
> -      if (!event)
> -         return VK_ERROR_OUT_OF_DATE_KHR;
> +
> +      if (timeout == UINT64_MAX) {
> +         event = xcb_wait_for_special_event(chain->conn, chain->special_event);
> +         if (!event)
> +            return VK_ERROR_OUT_OF_DATE_KHR;
> +      } else {
> +         event = xcb_poll_for_special_event(chain->conn, chain->special_event);
> +         if (!event) {
> +            int ret;
> +            if (timeout == 0)
> +               return VK_NOT_READY;
> +
> +            atimeout = wsi_get_absolute_timeout(timeout);
> +
> +            pfds.fd = xcb_get_file_descriptor(chain->conn);
> +            pfds.events = POLLIN;
> +            ret = poll(&pfds, 1, timeout / 1000 / 1000);
> +            if (ret == 0)
> +               return VK_NOT_READY;
> +            if (ret == -1)
> +               return VK_ERROR_OUT_OF_DATE_KHR;
> +
> +            /* If a non-special event happens, the fd will still
> +             * poll. So recalculate the timeout now just in case.
> +             */
> +            timeout = atimeout - wsi_get_current_time();
> +            continue;
> +         }
> +      }
>  
>        VkResult result = x11_handle_dri3_present_event(chain, (void *)event);
>        free(event);
> 

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