2017-03-02 10:09:01

by Daniel Vetter

[permalink] [raw]
Subject: Re: [PATCH v4 1/1] drm/fb-helper: implement ioctl FBIO_WAITFORVSYNC

On Tue, Feb 28, 2017 at 04:36:51PM +0100, Maxime Ripard wrote:
> 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.
>
> Signed-off-by: Maxime Ripard <[email protected]>
> Tested-by: Neil Armstrong <[email protected]>

Pushed to drm-misc, thanks.
-Daniel

> ---
> drivers/gpu/drm/drm_fb_helper.c | 68 ++++++++++++++++++++++++++++++++++-
> include/drm/drm_fb_helper.h | 12 +++++-
> 2 files changed, 79 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index c6de87abaca8..8ac8716c023a 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1240,6 +1240,74 @@ 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;
> + struct drm_mode_set *mode_set;
> + struct drm_crtc *crtc;
> + int ret = 0;
> +
> + mutex_lock(&dev->mode_config.mutex);
> + if (!drm_fb_helper_is_bound(fb_helper)) {
> + ret = -EBUSY;
> + goto unlock;
> + }
> +
> + switch (cmd) {
> + case FBIO_WAITFORVSYNC:
> + /*
> + * Only consider the first CRTC.
> + *
> + * This ioctl is supposed to take the CRTC number as
> + * an argument, but in fbdev times, what that number
> + * was supposed to be was quite unclear, different
> + * drivers were passing that argument differently
> + * (some by reference, some by value), and most of the
> + * userspace applications were just hardcoding 0 as an
> + * argument.
> + *
> + * The first CRTC should be the integrated panel on
> + * most drivers, so this is the best choice we can
> + * make. If we're not smart enough here, one should
> + * just consider switch the userspace to KMS.
> + */
> + mode_set = &fb_helper->crtc_info[0].mode_set;
> + crtc = mode_set->crtc;
> +
> + /*
> + * Only wait for a vblank event if the CRTC is
> + * enabled, otherwise just don't do anythintg,
> + * not even report an error.
> + */
> + ret = drm_crtc_vblank_get(crtc);
> + if (!ret) {
> + drm_crtc_wait_one_vblank(crtc);
> + drm_crtc_vblank_put(crtc);
> + }
> +
> + ret = 0;
> + goto unlock;
> + default:
> + ret = -ENOTTY;
> + }
> +
> +unlock:
> + mutex_unlock(&dev->mode_config.mutex);
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_fb_helper_ioctl);
> +
> +/**
> * drm_fb_helper_check_var - implementation for ->fb_check_var
> * @var: screeninfo to check
> * @info: fbdev registered by the helper
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index 975deedd593e..2891888c6e41 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -230,7 +230,8 @@ struct drm_fb_helper {
> .fb_blank = drm_fb_helper_blank, \
> .fb_pan_display = drm_fb_helper_pan_display, \
> .fb_debug_enter = drm_fb_helper_debug_enter, \
> - .fb_debug_leave = drm_fb_helper_debug_leave
> + .fb_debug_leave = drm_fb_helper_debug_leave, \
> + .fb_ioctl = drm_fb_helper_ioctl
>
> #ifdef CONFIG_DRM_FBDEV_EMULATION
> void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
> @@ -286,6 +287,9 @@ void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
>
> int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info);
>
> +int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
> + unsigned long arg);
> +
> int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper);
> int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel);
> int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper);
> @@ -377,6 +381,12 @@ static inline int drm_fb_helper_setcmap(struct fb_cmap *cmap,
> return 0;
> }
>
> +static inline int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
> + unsigned long arg)
> +{
> + return 0;
> +}
> +
> static inline void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper)
> {
> }
> --
> git-series 0.8.11
> _______________________________________________
> dri-devel mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


2017-03-02 10:09:26

by Daniel Vetter

[permalink] [raw]
Subject: Re: [PATCH v4 1/1] drm/fb-helper: implement ioctl FBIO_WAITFORVSYNC

On Thu, Mar 02, 2017 at 08:12:02AM +0100, Daniel Vetter wrote:
> On Tue, Feb 28, 2017 at 04:36:51PM +0100, Maxime Ripard wrote:
> > 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.
> >
> > Signed-off-by: Maxime Ripard <[email protected]>
> > Tested-by: Neil Armstrong <[email protected]>
>
> Pushed to drm-misc, thanks.

I forgot to add Dave's irc ack to the commit patch, but for the record I
discussed it with him and he's not enthuastic, but ok.
-Daniel

> -Daniel
>
> > ---
> > drivers/gpu/drm/drm_fb_helper.c | 68 ++++++++++++++++++++++++++++++++++-
> > include/drm/drm_fb_helper.h | 12 +++++-
> > 2 files changed, 79 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> > index c6de87abaca8..8ac8716c023a 100644
> > --- a/drivers/gpu/drm/drm_fb_helper.c
> > +++ b/drivers/gpu/drm/drm_fb_helper.c
> > @@ -1240,6 +1240,74 @@ 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;
> > + struct drm_mode_set *mode_set;
> > + struct drm_crtc *crtc;
> > + int ret = 0;
> > +
> > + mutex_lock(&dev->mode_config.mutex);
> > + if (!drm_fb_helper_is_bound(fb_helper)) {
> > + ret = -EBUSY;
> > + goto unlock;
> > + }
> > +
> > + switch (cmd) {
> > + case FBIO_WAITFORVSYNC:
> > + /*
> > + * Only consider the first CRTC.
> > + *
> > + * This ioctl is supposed to take the CRTC number as
> > + * an argument, but in fbdev times, what that number
> > + * was supposed to be was quite unclear, different
> > + * drivers were passing that argument differently
> > + * (some by reference, some by value), and most of the
> > + * userspace applications were just hardcoding 0 as an
> > + * argument.
> > + *
> > + * The first CRTC should be the integrated panel on
> > + * most drivers, so this is the best choice we can
> > + * make. If we're not smart enough here, one should
> > + * just consider switch the userspace to KMS.
> > + */
> > + mode_set = &fb_helper->crtc_info[0].mode_set;
> > + crtc = mode_set->crtc;
> > +
> > + /*
> > + * Only wait for a vblank event if the CRTC is
> > + * enabled, otherwise just don't do anythintg,
> > + * not even report an error.
> > + */
> > + ret = drm_crtc_vblank_get(crtc);
> > + if (!ret) {
> > + drm_crtc_wait_one_vblank(crtc);
> > + drm_crtc_vblank_put(crtc);
> > + }
> > +
> > + ret = 0;
> > + goto unlock;
> > + default:
> > + ret = -ENOTTY;
> > + }
> > +
> > +unlock:
> > + mutex_unlock(&dev->mode_config.mutex);
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(drm_fb_helper_ioctl);
> > +
> > +/**
> > * drm_fb_helper_check_var - implementation for ->fb_check_var
> > * @var: screeninfo to check
> > * @info: fbdev registered by the helper
> > diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> > index 975deedd593e..2891888c6e41 100644
> > --- a/include/drm/drm_fb_helper.h
> > +++ b/include/drm/drm_fb_helper.h
> > @@ -230,7 +230,8 @@ struct drm_fb_helper {
> > .fb_blank = drm_fb_helper_blank, \
> > .fb_pan_display = drm_fb_helper_pan_display, \
> > .fb_debug_enter = drm_fb_helper_debug_enter, \
> > - .fb_debug_leave = drm_fb_helper_debug_leave
> > + .fb_debug_leave = drm_fb_helper_debug_leave, \
> > + .fb_ioctl = drm_fb_helper_ioctl
> >
> > #ifdef CONFIG_DRM_FBDEV_EMULATION
> > void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
> > @@ -286,6 +287,9 @@ void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
> >
> > int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info);
> >
> > +int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
> > + unsigned long arg);
> > +
> > int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper);
> > int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel);
> > int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper);
> > @@ -377,6 +381,12 @@ static inline int drm_fb_helper_setcmap(struct fb_cmap *cmap,
> > return 0;
> > }
> >
> > +static inline int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
> > + unsigned long arg)
> > +{
> > + return 0;
> > +}
> > +
> > static inline void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper)
> > {
> > }
> > --
> > git-series 0.8.11
> > _______________________________________________
> > dri-devel mailing list
> > [email protected]
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch