Hi Geert,
Thank you for the patch.
On Thu, Jun 22, 2023 at 11:21:43AM +0200, Geert Uytterhoeven wrote:
> The DRM core vblank handling mechanism requires drivers to forcefully
> turn vblank reporting off when disabling the CRTC, and to restore the
> vblank reporting status when enabling the CRTC.
> Implement this using the drm_crtc_vblank_{on,off}() helpers.
>
> Note that drm_crtc_vblank_off() must be called at startup to synchronize
> the state of the vblank core code with the hardware, which is initially
> disabled. This is performed at CRTC creation time, requiring vertical
> blank initialization to be moved before creating CRTCs.
>
> Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
> ---
> drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c | 10 +++++++++-
> drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c | 12 ++++++------
> 2 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> index d2a0ac5f9368c11c..b184019d8b1ed89c 100644
> --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> @@ -267,6 +267,9 @@ static void shmob_drm_crtc_start(struct shmob_drm_crtc
> *scrtc)
>
> shmob_drm_crtc_start_stop(scrtc, true);
>
> + /* Turn vertical blank interrupt reporting back on. */
> + drm_crtc_vblank_on(crtc);
> +
> scrtc->started = true;
> }
>
> @@ -332,10 +335,12 @@ static void shmob_drm_crtc_stop(struct shmob_drm_crtc
> *scrtc)
> return;
>
> /*
> - * Wait for page flip completion before stopping the CRTC as userspace
> + * Disable vertical blank interrupt reporting. We first need to wait
> + * for page flip completion before stopping the CRTC as userspace
> * expects page flips to eventually complete.
> */
> shmob_drm_crtc_wait_page_flip(scrtc);
> + drm_crtc_vblank_off(crtc);
>
> /* Stop the LCDC. */
> shmob_drm_crtc_start_stop(scrtc, false);
> @@ -571,6 +576,9 @@ int shmob_drm_crtc_create(struct shmob_drm_device *sdev)
>
> drm_crtc_helper_add(crtc, &crtc_helper_funcs);
>
> + /* Start with vertical blank interrupt reporting disabled. */
> + drm_crtc_vblank_off(crtc);
> +
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> index 6eaf2c5a104f451a..a29c0c1093725b6e 100644
> --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> @@ -189,17 +189,17 @@ static int shmob_drm_probe(struct platform_device *pdev)
> if (ret < 0)
> return ret;
>
> - ret = shmob_drm_modeset_init(sdev);
> - if (ret < 0)
> - return dev_err_probe(&pdev->dev, ret,
> - "failed to initialize mode setting\n");
> -
> ret = drm_vblank_init(ddev, 1);
> if (ret < 0) {
> dev_err(&pdev->dev, "failed to initialize vblank\n");
> - goto err_modeset_cleanup;
> + return ret;
> }
>
> + ret = shmob_drm_modeset_init(sdev);
> + if (ret < 0)
> + return dev_err_probe(&pdev->dev, ret,
> + "failed to initialize mode setting\n");
> +
> ret = platform_get_irq(pdev, 0);
> if (ret < 0)
> goto err_modeset_cleanup;
--
Regards,
Laurent Pinchart
