[PATCH] drm/vkms: Add vblank events simulated by hrtimers
Rodrigo Siqueira
rodrigosiqueiramelo at gmail.com
Tue Jun 26 16:58:03 UTC 2018
On 06/26, Daniel Vetter wrote:
> On Tue, Jun 26, 2018 at 4:25 AM, Rodrigo Siqueira
> <rodrigosiqueiramelo at gmail.com> wrote:
> > On 06/25, Ville Syrjälä wrote:
> >> On Mon, Jun 25, 2018 at 02:19:22PM -0300, Rodrigo Siqueira wrote:
> >> > This commit adds regular vblank events simulated through hrtimers, which
> >> > is a feature required by VKMS to mimic real hardware. In this sense,
> >> > this commit adopts a default frequency of 60Hz for vblank interval.
> >> > Finally, this commit implements handlers for some of the atomic and
> >> > vblank hooks.
> >> >
> >> > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> >> > ---
> >> > Note:
> >> > - This patch depends on the patchset "drm/vkms: Updates to meet basic
> >> > kms_flip requirements"
> >> > link: https://lists.freedesktop.org/archives/dri-devel/2018-June/180823.html
> >> >
> >> > drivers/gpu/drm/vkms/vkms_crtc.c | 90 +++++++++++++++++++++++++++++++-
> >> > drivers/gpu/drm/vkms/vkms_drv.c | 6 +++
> >> > drivers/gpu/drm/vkms/vkms_drv.h | 9 ++++
> >> > 3 files changed, 103 insertions(+), 2 deletions(-)
> >> >
> >> > diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> >> > index 84cc05506b09..73aae129c37d 100644
> >> > --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> >> > +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> >> > @@ -10,6 +10,52 @@
> >> > #include <drm/drm_atomic_helper.h>
> >> > #include <drm/drm_crtc_helper.h>
> >> >
> >> > +static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
> >> > +{
> >> > + struct vkms_output *output = container_of(timer, struct vkms_output,
> >> > + vblank_hrtimer);
> >> > + struct drm_crtc *crtc = &output->crtc;
> >> > + unsigned long flags;
> >> > + int ret_overrun;
> >> > + bool ret;
> >> > +
> >> > + ret = drm_crtc_handle_vblank(&output->crtc);
> >> > + if (!ret)
> >> > + DRM_ERROR("vkms failure on handling vblank");
> >> > +
> >> > + spin_lock_irqsave(&crtc->dev->event_lock, flags);
> >> > + if (output->event) {
> >> > + drm_crtc_send_vblank_event(crtc, output->event);
> >> > + drm_crtc_vblank_put(crtc);
> >> > + output->event = NULL;
> >> > + }
> >> > + spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> >> > +
> >> > + ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
> >> > + output->period_ns);
> >> > +
> >> > + return HRTIMER_RESTART;
> >> > +}
> >> > +
> >> > +static int vkms_enable_vblank(struct drm_crtc *crtc)
> >> > +{
> >> > + struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
> >> > +
> >> > + hrtimer_init(&out->vblank_hrtimer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
> >> > + out->vblank_hrtimer.function = &vkms_vblank_simulate;
> >> > + out->period_ns = ktime_set(0, DEFAULT_VBLANK_NS);
> >>
> >> Don't you want the vblank interval to roughly match the crtc timings the
> >> user asked for?
> > Hi,
> >
> > We want to provide interactions with users by allowing them to specify
> > the Vblank interval (and maybe other things); I hardcoded it for
> > simplicity sake since my focus now it is simulates real hardware and
> > later virtual hardware. However, IMHO the best way to provide this
> > interaction in the VKMS is via sysfs; another option could be use a
> > module parameter especified during the load, but I'm not sure if
> > this is a good approach.
> >
> > Thanks for your feedback
>
> Nah, we want that the the mode we simulate is the mode userspace
> requested. That's how real hardware works.
>
> For simulating virtual hardware the rules are slightly different:
> There's no vblank support at all, and page flip events complete
> immediately (or as long as it takes the virtual hw to upload the
> buffers for display, if there's some copying involved).
> drm_calc_timestamping_constants() is the helper you can use to
> compute/fill in the necessary constants, but the atomic helpers do
> that for you already. Note that you can't access
> drm_crtc->state.requested_mode from the vblank handler, since your
> hrtimer does not hold the required locks.
>
> kms_flip should complain about the timestamps not matching with the
> requested mode without this. You might need to force a specific edid
> with a vrefresh that doesn't match your hardcoded one though to
> actually see the bug.
> -Daniel
I think I understood your points, and I already started to work on a new
version. First, I will focus on the real hardware simulation and try to
make all the kms_flip tests pass (at this moment around 1/3 of the tests
are passing). I will talk with you in the irc for trying to better
understand the details.
Thanks
> > Best Regards,
> > Rodrigo Siqueira
> >
> >> > + hrtimer_start(&out->vblank_hrtimer, out->period_ns, HRTIMER_MODE_ABS);
> >> > +
> >> > + return 0;
> >> > +}
> >> > +
> >> > +static void vkms_disable_vblank(struct drm_crtc *crtc)
> >> > +{
> >> > + struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
> >> > +
> >> > + hrtimer_cancel(&out->vblank_hrtimer);
> >> > +}
> >> > +
> >> > static const struct drm_crtc_funcs vkms_crtc_funcs = {
> >> > .set_config = drm_atomic_helper_set_config,
> >> > .destroy = drm_crtc_cleanup,
> >> > @@ -17,6 +63,8 @@ static const struct drm_crtc_funcs vkms_crtc_funcs = {
> >> > .reset = drm_atomic_helper_crtc_reset,
> >> > .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> >> > .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> >> > + .enable_vblank = vkms_enable_vblank,
> >> > + .disable_vblank = vkms_disable_vblank,
> >> > };
> >> >
> >> > static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
> >> > @@ -27,12 +75,50 @@ static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
> >> >
> >> > static void vkms_crtc_atomic_enable(struct drm_crtc *crtc,
> >> > struct drm_crtc_state *old_state)
> >> > +{
> >> > + drm_crtc_vblank_on(crtc);
> >> > +}
> >> > +
> >> > +static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
> >> > + struct drm_crtc_state *old_s)
> >> > +{
> >> > + struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
> >> > +
> >> > + if (crtc->state->event) {
> >> > + crtc->state->event->pipe = drm_crtc_index(crtc);
> >> > + WARN_ON(drm_crtc_vblank_get(crtc) != 0);
> >> > +
> >> > + vkms_output->event = crtc->state->event;
> >> > + crtc->state->event = NULL;
> >> > + }
> >> > +}
> >> > +
> >> > +static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
> >> > + struct drm_crtc_state *old_crtc_state)
> >> > +{
> >> > + struct drm_pending_vblank_event *event = crtc->state->event;
> >> > +
> >> > + if (!event)
> >> > + return;
> >> > +
> >> > + crtc->state->event = NULL;
> >> > +
> >> > + spin_lock_irq(&crtc->dev->event_lock);
> >> > + if (drm_crtc_vblank_get(crtc))
> >> > + drm_crtc_send_vblank_event(crtc, event);
> >> > + spin_unlock_irq(&crtc->dev->event_lock);
> >> > +}
> >> > +
> >> > +static void vkms_crtc_commit(struct drm_crtc *crtc)
> >> > {
> >> > }
> >> >
> >> > static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = {
> >> > - .atomic_check = vkms_crtc_atomic_check,
> >> > - .atomic_enable = vkms_crtc_atomic_enable,
> >> > + .atomic_check = vkms_crtc_atomic_check,
> >> > + .atomic_enable = vkms_crtc_atomic_enable,
> >> > + .atomic_flush = vkms_crtc_atomic_flush,
> >> > + .atomic_begin = vkms_crtc_atomic_begin,
> >> > + .commit = vkms_crtc_commit,
> >> > };
> >> >
> >> > int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
> >> > diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> >> > index fe93f8c17997..c56d66d9ec56 100644
> >> > --- a/drivers/gpu/drm/vkms/vkms_drv.c
> >> > +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> >> > @@ -102,6 +102,12 @@ static int __init vkms_init(void)
> >> > goto out_fini;
> >> > }
> >> >
> >> > + ret = drm_vblank_init(&vkms_device->drm, 1);
> >> > + if (ret) {
> >> > + DRM_ERROR("Failed to vblank\n");
> >> > + goto out_fini;
> >> > + }
> >> > +
> >> > ret = vkms_modeset_init(vkms_device);
> >> > if (ret)
> >> > goto out_unregister;
> >> > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> >> > index 76f1720f81a5..f115e7d1ae03 100644
> >> > --- a/drivers/gpu/drm/vkms/vkms_drv.h
> >> > +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> >> > @@ -5,6 +5,7 @@
> >> > #include <drm/drm.h>
> >> > #include <drm/drm_gem.h>
> >> > #include <drm/drm_encoder.h>
> >> > +#include <linux/hrtimer.h>
> >> >
> >> > #define XRES_MIN 32
> >> > #define YRES_MIN 32
> >> > @@ -15,6 +16,8 @@
> >> > #define XRES_MAX 8192
> >> > #define YRES_MAX 8192
> >> >
> >> > +#define DEFAULT_VBLANK_NS 16666666
> >> > +
> >> > static const u32 vkms_formats[] = {
> >> > DRM_FORMAT_XRGB8888,
> >> > };
> >> > @@ -23,6 +26,9 @@ struct vkms_output {
> >> > struct drm_crtc crtc;
> >> > struct drm_encoder encoder;
> >> > struct drm_connector connector;
> >> > + struct hrtimer vblank_hrtimer;
> >> > + ktime_t period_ns;
> >> > + struct drm_pending_vblank_event *event;
> >> > };
> >> >
> >> > struct vkms_device {
> >> > @@ -37,6 +43,9 @@ struct vkms_gem_object {
> >> > struct page **pages;
> >> > };
> >> >
> >> > +#define drm_crtc_to_vkms_output(target) \
> >> > + container_of(target, struct vkms_output, crtc)
> >> > +
> >> > int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
> >> > struct drm_plane *primary, struct drm_plane *cursor);
> >> >
> >> > --
> >> > 2.17.1
> >> >
> >> > _______________________________________________
> >> > dri-devel mailing list
> >> > dri-devel at lists.freedesktop.org
> >> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >>
> >> --
> >> Ville Syrjälä
> >> Intel
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
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