linux-kernel - Re: [PATCH 2/3] drm/mediatek: make sure previous message done or be aborted before send

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Message-ID: <1581662912.17949.4.camel@mtksdaap41>
Date:   Fri, 14 Feb 2020 14:48:32 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     Bibby Hsieh <bibby.hsieh@...iatek.com>
CC:     David Airlie <airlied@...ux.ie>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        <dri-devel@...ts.freedesktop.org>,
        <linux-mediatek@...ts.infradead.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        YT Shen <yt.shen@...iatek.com>,
        Thierry Reding <thierry.reding@...il.com>,
        <linux-arm-kernel@...ts.infradead.org>, <tfiga@...omium.org>,
        <drinkcat@...omium.org>, <linux-kernel@...r.kernel.org>,
        <srv_heupstream@...iatek.com>
Subject: Re: [PATCH 2/3] drm/mediatek: make sure previous message done or be
 aborted before send

Hi, Bibby:

On Fri, 2020-02-14 at 12:49 +0800, Bibby Hsieh wrote:
> Mediatek CMDQ driver removed atomic parameter and implementation
> related to atomic. DRM driver need to make sure previous message
> done or be aborted before we send next message.
> 
> If previous message is still waiting for event, it means the
> setting hasn't been updated into display hardware register,
> we can abort the message and send next message to update the
> newest setting into display hardware.
> If previous message already started, we have to wait it until
> transmission has been completed.
> 
> So we flush mbox client before we send new message to controller
> driver.
> 

Reviewed-by: CK Hu <ck.hu@...iatek.com>

> This patch depends on ptach:
> [0/3] Remove atomic_exec
> https://patchwork.kernel.org/cover/11381677/
> 
> Signed-off-by: Bibby Hsieh <bibby.hsieh@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index 3c53ea22208c..e35b66c5ba0f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -491,6 +491,7 @@ static void mtk_drm_crtc_hw_config(struct mtk_drm_crtc *mtk_crtc)
>  	}
>  #if IS_ENABLED(CONFIG_MTK_CMDQ)
>  	if (mtk_crtc->cmdq_client) {
> +		mbox_flush(mtk_crtc->cmdq_client->chan, 2000);
>  		cmdq_handle = cmdq_pkt_create(mtk_crtc->cmdq_client, PAGE_SIZE);
>  		cmdq_pkt_clear_event(cmdq_handle, mtk_crtc->cmdq_event);
>  		cmdq_pkt_wfe(cmdq_handle, mtk_crtc->cmdq_event);