Hi Sui,
On Sat, Jun 24, 2023 at 11:33 AM Sui Jingfeng <suijingfeng@xxxxxxxxxxx> wrote:
> I'm fine with this patch but I I don't see the benefit.
>
> This reply is more about my personal question.
>
> On 2023/6/22 17:21, Geert Uytterhoeven wrote:
> > Replace the call to the legacy drm_handle_vblank() function with a call
> > to the new drm_crtc_handle_vblank() helper.
> >
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> Reviewed-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> > index c98e2bdd888c3274..6eaf2c5a104f451a 100644
> > --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> > +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> > @@ -86,7 +86,7 @@ static irqreturn_t shmob_drm_irq(int irq, void *arg)
> > spin_unlock_irqrestore(&sdev->irq_lock, flags);
> >
> > if (status & LDINTR_VES) {
> > - drm_handle_vblank(dev, 0);
> > + drm_crtc_handle_vblank(&sdev->crtc.base);
>
>
> After switching to drm_crtc_handle_vblank(),
>
> your driver need another deference to the pointer of 'struct drm_crtc'
> to get the pointer of 'struct drm_device';
>
> Plus another call to get the index(display pipe) of the CRTC by calling
> drm_crtc_index(crtc).
That is correct.
> Consider that shmob-drm support only one display pipe,
>
> is it that the switching is less straight forward than the original
> implement ?
>
>
> ```
>
> /**
> * drm_crtc_handle_vblank - handle a vblank event
> * @crtc: where this event occurred
> *
> * Drivers should call this routine in their vblank interrupt handlers to
> * update the vblank counter and send any signals that may be pending.
> *
> * This is the native KMS version of drm_handle_vblank().
> *
> * Note that for a given vblank counter value drm_crtc_handle_vblank()
> * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
> * provide a barrier: Any writes done before calling
> * drm_crtc_handle_vblank() will be visible to callers of the later
> * functions, if the vblank count is the same or a later one.
> *
> * See also &drm_vblank_crtc.count.
> *
> * Returns:
> * True if the event was successfully handled, false on failure.
> */
> bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
> {
> return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
> }
>
> ```
>
> Is it that drm_crtc_handle_vblank() function is preferred over
> drm_handle_vblank() in the future?
>
> I'm fine with this question answered.
I think the native KMS version is preferred over the legacy version, cfr.
/**
* drm_handle_vblank - handle a vblank event
[...]
* This is the legacy version of drm_crtc_handle_vblank().
*/
bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
