linux-kernel - Re: [PATCH] DRM: UDL: get rid of useless vblank initialization

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Date:   Mon, 1 Oct 2018 10:14:08 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>
Cc:     dri-devel@...ts.freedesktop.org, David Airlie <airlied@...ux.ie>,
        Alexey Brodkin <alexey.brodkin@...opsys.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Stéphane Marchesin <marcheu@...omium.org>,
        linux-snps-arc@...ts.infradead.org, Sean Paul <sean@...rly.run>
Subject: Re: [PATCH] DRM: UDL: get rid of useless vblank initialization

On Fri, Sep 28, 2018 at 05:41:26PM +0300, Eugeniy Paltsev wrote:
> UDL doesn't support vblank functionality so we don't need to
> initialize vblank here (we are able to send page flip
> completion events even without vblank initialization)
> 
> Moreover current drm_vblank_init call with num_crtcs > 0 causes
> sending DRM_EVENT_FLIP_COMPLETE event with zero timestamp every
> time. This breaks userspace apps (for example weston) which
> relies on timestamp value.
> 
> Cc: stable@...r.kernel.org
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>

Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>

> ---
>  drivers/gpu/drm/udl/udl_main.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
> index f455f095a146..1b014d92855b 100644
> --- a/drivers/gpu/drm/udl/udl_main.c
> +++ b/drivers/gpu/drm/udl/udl_main.c
> @@ -350,15 +350,10 @@ int udl_driver_load(struct drm_device *dev, unsigned long flags)
>  	if (ret)
>  		goto err;
>  
> -	ret = drm_vblank_init(dev, 1);
> -	if (ret)
> -		goto err_fb;
> -
>  	drm_kms_helper_poll_init(dev);
>  
>  	return 0;
> -err_fb:
> -	udl_fbdev_cleanup(dev);
> +
>  err:
>  	if (udl->urbs.count)
>  		udl_free_urb_list(dev);
> -- 
> 2.14.4
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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