linux-kernel - Re: [PATCH v4] drm/mediatek: allow commands to be sent during video mode

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Message-ID: <CAAOTY_82E2BK1cxwbsDsj5DURrY245Xnd-04N=4vevCRMjkZpw@mail.gmail.com>
Date:   Thu, 17 Feb 2022 23:15:47 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Cc:     Julien STEPHAN <jstephan@...libre.com>,
        Mattijs Korpershoek <mkorpershoek@...libre.com>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "open list:DRM DRIVERS FOR MEDIATEK" 
        <dri-devel@...ts.freedesktop.org>,
        "moderated list:DRM DRIVERS FOR MEDIATEK" 
        <linux-mediatek@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] drm/mediatek: allow commands to be sent during video mode

 [1Hi, Julien:

AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com> 於
2022年2月14日 週一 下午5:43寫道：
>
> Il 14/02/22 10:27, Julien STEPHAN ha scritto:
> > Mipi dsi panel drivers can use mipi_dsi_dcs_{set,get}_display_brightness()
> > to request backlight changes.
> >
> > This can be done during panel initialization (dsi is in command mode)
> > or afterwards (dsi is in Video Mode).
> >
> > When the DSI is in Video Mode, all commands are rejected.
> >
> > Detect current DSI mode in mtk_dsi_host_transfer() and switch modes
> > temporarily to allow commands to be sent.

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
Chun-Kuang.

> >
> > Signed-off-by: Julien STEPHAN <jstephan@...libre.com>
> > Signed-off-by: Mattijs Korpershoek <mkorpershoek@...libre.com>
>
> Please, next time, don't drop the tags that reviewers are giving to you, unless
> the patch changes radically.
>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
>
> > ---
> > Changes in v4:
> >      - fix missing space:  "ret : recv_cnt;"
> > Changes in v3:
> >      - increase readability of code and use correct return variable (see
> >        comment
> > https://lore.kernel.org/linux-mediatek/4907bdc1-b4a6-e9ad-5cfa-266fc20c0bec@collabora.com/)
> >
> > Changes in v2:
> >      - update commit message to be more descriptive
> >
> >   drivers/gpu/drm/mediatek/mtk_dsi.c | 33 ++++++++++++++++++++++--------
> >   1 file changed, 24 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index 5d90d2eb0019..abdd9cdebd86 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -891,24 +891,33 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
> >       u8 read_data[16];
> >       void *src_addr;
> >       u8 irq_flag = CMD_DONE_INT_FLAG;
> > +     u32 dsi_mode;
> > +     int ret;
> >
> > -     if (readl(dsi->regs + DSI_MODE_CTRL) & MODE) {
> > -             DRM_ERROR("dsi engine is not command mode\n");
> > -             return -EINVAL;
> > +     dsi_mode = readl(dsi->regs + DSI_MODE_CTRL);
> > +     if (dsi_mode & MODE) {
> > +             mtk_dsi_stop(dsi);
> > +             ret = mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
> > +             if (ret)
> > +                     goto restore_dsi_mode;
> >       }
> >
> >       if (MTK_DSI_HOST_IS_READ(msg->type))
> >               irq_flag |= LPRX_RD_RDY_INT_FLAG;
> >
> > -     if (mtk_dsi_host_send_cmd(dsi, msg, irq_flag) < 0)
> > -             return -ETIME;
> > +     ret = mtk_dsi_host_send_cmd(dsi, msg, irq_flag);
> > +     if (ret)
> > +             goto restore_dsi_mode;
> >
> > -     if (!MTK_DSI_HOST_IS_READ(msg->type))
> > -             return 0;
> > +     if (!MTK_DSI_HOST_IS_READ(msg->type)) {
> > +             recv_cnt = 0;
> > +             goto restore_dsi_mode;
> > +     }
> >
> >       if (!msg->rx_buf) {
> >               DRM_ERROR("dsi receive buffer size may be NULL\n");
> > -             return -EINVAL;
> > +             ret = -EINVAL;
> > +             goto restore_dsi_mode;
> >       }
> >
> >       for (i = 0; i < 16; i++)
> > @@ -933,7 +942,13 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
> >       DRM_INFO("dsi get %d byte data from the panel address(0x%x)\n",
> >                recv_cnt, *((u8 *)(msg->tx_buf)));
> >
> > -     return recv_cnt;
> > +restore_dsi_mode:
> > +     if (dsi_mode & MODE) {
> > +             mtk_dsi_set_mode(dsi);
> > +             mtk_dsi_start(dsi);
> > +     }
> > +
> > +     return ret < 0 ? ret : recv_cnt;
> >   }
> >
> >   static const struct mipi_dsi_host_ops mtk_dsi_ops = {
> > --
> > 2.35.1
> >
>
>
>