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From:   Pintu Agarwal <pintu.ping@gmail.com>
Date:   Wed, 19 Jun 2019 20:34:55 +0530
Message-ID: <CAOuPNLhZhgN26rquLQq9zHBct1QxK-7hXAza0xk-0QooPGYLNw@mail.gmail.com>
Subject: Re: [IMX] [DRM]: suspend/resume support
To:     Fabio Estevam <festevam@gmail.com>
Cc:     open list <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        Kernelnewbies <kernelnewbies@kernelnewbies.org>,
        linux-pm@vger.kernel.org
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On Wed, Jun 19, 2019 at 7:14 PM Fabio Estevam <festevam@gmail.com> wrote:
>
> On Wed, Jun 19, 2019 at 10:33 AM Pintu Agarwal <pintu.ping@gmail.com> wrote:
>
> > You can think that the version I am using right now is almost 4.9 itself.
>
> "almost 4.9" does not help, sorry.
>
> > Upgrading again to higher kernel version is again difficult, also
> > customer does not want it.
>
> dw-hdmi is well supported on i.MX6 with mainline, so you could simply try that.
>
> Try booting 5.1.11 on your custom board with a very minimal dts with
> HDMI support.
>
Okay. I will surely try it on another IMX6 fresh board.
With 5.1.11 you mean the kernel from mainline kernel.org
Or, is there a separate kernel repo for imx6. If yes, please let me know.

> Then you can test suspend/resume and see if HDMI hangs or not.
>
By this suspend/resume, you mean "suspend-to-ram" or "suspend-to-disk" ?

> > Another approach I tried is, installing hdmi {dw-hdmi.ko,
> > dw_hdmi-imx.ko} as a module, just after the resume.
> > With this also system hangs during installation of dw_hdmi-imx.ko at
> > below location:
> >
> > imx_drm_driver_load(..)
> > |
> > |--> component_bind_all(...)
> >      |
> >      |-> component_bind(ipu)
> >          |
> >          |
> >          ipu_drm_bind(..)
> >          |
> >          |-> ipu_crtc_init(..)
> >              |
> >              |-> ipu_plane_irq(..)
> >              |
> >              | ----> << __HANGS HERE__ >>
>
> I am not able to reproduce this hang. As I mentioned yesterday
> suspend/resume is working just fine.
>
This scenario is not with suspend/resume.
This hang is, when we make hdmi as a loadable module (.ko) and trying
to install it after resume.
In this case, suspend/resume will not come into picture. Not sure why
it still hangs.
Do you have any clue for this scenario?