On 2020-03-09 20:52, Laurent Pinchart wrote:
> Enable vblank handling when the CRTC is turned on and disable it when it
> is turned off. This requires moving vblank init after the KMS pipeline
> initialisation, otherwise drm_vblank_init() gets called with 0 CRTCs.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
With this patch applied I start to get system resets on my Colibri iMX7
test device during system boot shortly after initializing mxsfb. It
happens not on every boot, but rather often, I would say every second or
third. From what I can tell the interrupt handling should be safe, but
it seems that every now and then something races. Any idea what that
could be?
--
Stefan
> ---
> drivers/gpu/drm/mxsfb/mxsfb_drv.c | 15 +++++++++------
> drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
> 2 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> index e324bd2a63a5..72b4f6a947a4 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> @@ -160,12 +160,6 @@ static int mxsfb_load(struct drm_device *drm,
> unsigned long flags)
>
> pm_runtime_enable(drm->dev);
>
> - ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
> - if (ret < 0) {
> - dev_err(drm->dev, "Failed to initialise vblank\n");
> - goto err_vblank;
> - }
> -
> /* Modeset init */
> drm_mode_config_init(drm);
>
> @@ -175,6 +169,15 @@ static int mxsfb_load(struct drm_device *drm,
> unsigned long flags)
> goto err_vblank;
> }
>
> + ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
> + if (ret < 0) {
> + dev_err(drm->dev, "Failed to initialise vblank\n");
> + goto err_vblank;
> + }
> +
> + /* Start with vertical blanking interrupt reporting disabled. */
> + drm_crtc_vblank_off(&mxsfb->crtc);
> +
> ret = mxsfb_attach_bridge(mxsfb);
> if (ret) {
> dev_err(drm->dev, "Cannot connect bridge: %d\n", ret);
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> index ac2696c8483d..640305fb1068 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> @@ -322,8 +322,10 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
> dma_addr_t paddr;
>
> pm_runtime_get_sync(drm->dev);
> -
> mxsfb_enable_axi_clk(mxsfb);
> +
> + drm_crtc_vblank_on(crtc);
> +
> mxsfb_crtc_mode_set_nofb(mxsfb);
>
> /* Write cur_buf as well to avoid an initial corrupt frame */
> @@ -353,6 +355,8 @@ static void mxsfb_crtc_atomic_disable(struct drm_crtc *crtc,
> }
> spin_unlock_irq(&drm->event_lock);
>
> + drm_crtc_vblank_off(crtc);
> +
> mxsfb_disable_axi_clk(mxsfb);
> pm_runtime_put_sync(drm->dev);
> }
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