On Mon, Feb 13, 2017 at 11:35:18AM +0100, Maxime Ripard wrote: > Hi Ville, > > On Fri, Feb 10, 2017 at 04:06:05PM +0200, Ville Syrjälä wrote: > > On Thu, Feb 02, 2017 at 11:31:57AM +0100, Maxime Ripard wrote: > > > From: Stefan Christ <s.christ@xxxxxxxxx> > > > > > > Implement legacy framebuffer ioctl FBIO_WAITFORVSYNC in the generic > > > framebuffer emulation driver. Legacy framebuffer users like non kms/drm > > > based OpenGL(ES)/EGL implementations may require the ioctl to > > > synchronize drawing or buffer flip for double buffering. It is tested on > > > the i.MX6. > > > > > > Code is based on > > > https://github.com/Xilinx/linux-xlnx/blob/master/drivers/gpu/drm/xilinx/xilinx_drm_fb.c#L196 > > > > > > Signed-off-by: Stefan Christ <s.christ@xxxxxxxxx> > > > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> > > > --- > > > drivers/gpu/drm/drm_fb_helper.c | 55 ++++++++++++++++++++++++++++++++++- > > > include/drm/drm_fb_helper.h | 5 ++- > > > 2 files changed, 59 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c > > > index e934b541feea..39a3532e311c 100644 > > > --- a/drivers/gpu/drm/drm_fb_helper.c > > > +++ b/drivers/gpu/drm/drm_fb_helper.c > > > @@ -1234,6 +1234,61 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info) > > > EXPORT_SYMBOL(drm_fb_helper_setcmap); > > > > > > /** > > > + * drm_fb_helper_ioctl - legacy ioctl implementation > > > + * @info: fbdev registered by the helper > > > + * @cmd: ioctl command > > > + * @arg: ioctl argument > > > + * > > > + * A helper to implement the standard fbdev ioctl. Only > > > + * FBIO_WAITFORVSYNC is implemented for now. > > > + */ > > > +int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg) > > > +{ > > > + struct drm_fb_helper *fb_helper = info->par; > > > + struct drm_device *dev = fb_helper->dev; > > > + unsigned int i; > > > + int ret = 0; > > > + > > > + drm_modeset_lock_all(dev); > > > + if (!drm_fb_helper_is_bound(fb_helper)) { > > > + drm_modeset_unlock_all(dev); > > > + return -EBUSY; > > > + } > > > + > > > + switch (cmd) { > > > + case FBIO_WAITFORVSYNC: > > > + for (i = 0; i < fb_helper->crtc_count; i++) { > > > > FBIO_WAITFORVSYNC takes the crtc as a parmeter, so I'm not sure we want > > to do this for all the crtcs. Though what that crtc means for fb is > > rather poorly defined. > > I guess I could just use that index to retrieve only the right CRTC in > fb_helper->crtc_info. > > > > > > + struct drm_mode_set *mode_set; > > > + struct drm_crtc *crtc; > > > + > > > + mode_set = &fb_helper->crtc_info[i].mode_set; > > > + crtc = mode_set->crtc; > > > + > > > + /* > > > + * Only call drm_crtc_wait_one_vblank for crtcs that > > > + * are currently enabled. > > > + */ > > > + if (!crtc->enabled) > > > + continue; > > > + > > > + ret = drm_crtc_vblank_get(crtc); > > > + if (!ret) { > > > + drm_crtc_wait_one_vblank(crtc); > > > + drm_crtc_vblank_put(crtc); > > > + } > > > > This looks quite sub-optimal. It should rather do something along the > > lines of what drm_atomic_helper_wait_for_vblanks() does. > > How is that suboptimal? You're serializing the waits rather than doing them in parallel. Let's look at a simple three crtc example (|=vblank): time --> CRTC 1: | | | | CRTC 2: | | | | CRTC 3: | | | | Your code waits until here: | | | 1 2 3 ^ Optimal code would wait until here: | ^ -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
