Re: [PATCH v2 2/7] drm: mxsfb: Simplify LCDIF IRQ handling

[Lucas Stach <l.stach@pengutronix.de>]

Am Freitag, dem 11.03.2022 um 18:05 +0100 schrieb Marek Vasut:
> The call to drm_crtc_vblank_off(&lcdif->crtc); disables IRQ generation
> from the LCDIF block already and this is called in mxsfb_load() before
> request_irq(), so explicitly disabling IRQ using custom function like
> mxsfb_irq_disable() is not needed, remove it.
> 

Have you checked that the drm_vblank_off in probe actually results in a
call to mxsfb_crtc_disable_vblank? From my reading of the core code,
this should be a no-op without a previous drm_vblank_on, so it would
not result in the desired masking before the IRQ is requested.

Regards,
Lucas

>  The request_irq() call
> would return -ENOTCONN if IRQ is IRQ_NOTCONNECTED already, so remove
> the unnecessary check. Finally, remove both mxsfb_irq_install() and
> mxsfb_irq_uninstall() as well, since they are no longer useful.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Alexander Stein <alexander.stein@ew.tq-group.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: Peng Fan <peng.fan@nxp.com>
> Cc: Robby Cai <robby.cai@nxp.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: Stefan Agner <stefan@agner.ch>
> ---
> V2: No change
> ---
>  drivers/gpu/drm/mxsfb/mxsfb_drv.c | 38 +++++++------------------------
>  1 file changed, 8 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> index c790aeff0a6f0..94cafff7f68d5 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> @@ -157,33 +157,6 @@ static irqreturn_t mxsfb_irq_handler(int irq, void *data)
>  	return IRQ_HANDLED;
>  }
>  
> -static void mxsfb_irq_disable(struct drm_device *drm)
> -{
> -	struct mxsfb_drm_private *mxsfb = drm->dev_private;
> -
> -	/* Disable and clear VBLANK IRQ */
> -	writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_CLR);
> -	writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
> -}
> -
> -static int mxsfb_irq_install(struct drm_device *dev, int irq)
> -{
> -	if (irq == IRQ_NOTCONNECTED)
> -		return -ENOTCONN;
> -
> -	mxsfb_irq_disable(dev);
> -
> -	return request_irq(irq, mxsfb_irq_handler, 0,  dev->driver->name, dev);
> -}
> -
> -static void mxsfb_irq_uninstall(struct drm_device *dev)
> -{
> -	struct mxsfb_drm_private *mxsfb = dev->dev_private;
> -
> -	mxsfb_irq_disable(dev);
> -	free_irq(mxsfb->irq, dev);
> -}
> -
>  static int mxsfb_load(struct drm_device *drm,
>  		      const struct mxsfb_devdata *devdata)
>  {
> @@ -259,7 +232,8 @@ static int mxsfb_load(struct drm_device *drm,
>  		return ret;
>  	mxsfb->irq = ret;
>  
> -	ret = mxsfb_irq_install(drm, mxsfb->irq);
> +	ret = request_irq(mxsfb->irq, mxsfb_irq_handler, 0,
> +			  drm->driver->name, drm);
>  	if (ret < 0) {
>  		dev_err(drm->dev, "Failed to install IRQ handler\n");
>  		return ret;
> @@ -276,16 +250,20 @@ static int mxsfb_load(struct drm_device *drm,
>  
>  static void mxsfb_unload(struct drm_device *drm)
>  {
> +	struct mxsfb_drm_private *mxsfb = drm->dev_private;
> +
>  	pm_runtime_get_sync(drm->dev);
>  
> +	drm_crtc_vblank_off(&mxsfb->crtc);
> +
>  	drm_kms_helper_poll_fini(drm);
>  	drm_mode_config_cleanup(drm);
>  
> -	mxsfb_irq_uninstall(drm);
> -
>  	pm_runtime_put_sync(drm->dev);
>  	pm_runtime_disable(drm->dev);
>  
> +	free_irq(mxsfb->irq, drm->dev);
> +
>  	drm->dev_private = NULL;
>  }
>