Re: [PATCH v1 05/11] drm/vblank: drop use of DRM_WAIT_ON()

Sean Paul
2019-07-18T17:50:58Z

On Thu, Jul 18, 2019 at 06:15:01PM +0200, Sam Ravnborg wrote:
> DRM_WAIT_ON() is from the deprecated drm_os_linux header and
> the modern replacement is the wait_event_*.
>
> The return values differ, so a conversion is needed to
> keep the original interface towards userspace.
> Introduced a switch/case to make code obvious and to allow
> different debug prints depending on the result.
>
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Reviewed-by: Sean Paul <sean@poorly.run>

> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> Cc: Sean Paul <sean@poorly.run>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> ---
> drivers/gpu/drm/drm_vblank.c | 29 ++++++++++++++++++++---------
> 1 file changed, 20 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> index 603ab105125d..8e9ac187500e 100644
> --- a/drivers/gpu/drm/drm_vblank.c
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -31,7 +31,6 @@
> #include <drm/drm_drv.h>
> #include <drm/drm_framebuffer.h>
> #include <drm/drm_print.h>
> -#include <drm/drm_os_linux.h>
> #include <drm/drm_vblank.h>
>
> #include "drm_internal.h"
> @@ -1672,19 +1671,31 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
> if (req_seq != seq) {
> DRM_DEBUG("waiting on vblank count %llu, crtc %u\n",
> req_seq, pipe);
> - DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
> - vblank_passed(drm_vblank_count(dev, pipe),
> - req_seq) ||
> - !READ_ONCE(vblank->enabled));
> + ret = wait_event_interruptible_timeout(vblank->queue,
> + vblank_passed(drm_vblank_count(dev, pipe), req_seq) ||
> + !READ_ONCE(vblank->enabled),
> + msecs_to_jiffies(3000));
> }
>
> - if (ret != -EINTR) {
> + switch (ret) {
> + case 0:
> + /* timeout */
> + ret = -EBUSY;
> drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
> -
> - DRM_DEBUG("crtc %d returning %u to client\n",
> + DRM_DEBUG("timeout waiting for vblank. crtc %d returning %u to client\n",
> pipe, vblwait->reply.sequence);
> - } else {
> + break;
> + case -ERESTARTSYS:
> + /* interrupted by signal */
> + ret = -EINTR;
> DRM_DEBUG("crtc %d vblank wait interrupted by signal\n", pipe);
> + break;
> + default:
> + ret = 0;
> + drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
> + DRM_DEBUG("crtc %d returning %u to client\n",
> + pipe, vblwait->reply.sequence);
> + break;
> }
>
> done:
> --
> 2.20.1
>

--
Sean Paul, Software Engineer, Google / Chromium OS