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From: Inki Dae <inki.dae@samsung.com>
To: Naveen Krishna Ch <naveenkrishna.ch@gmail.com>
Cc: "linux-samsung-soc@vger.kernel.org"
	<linux-samsung-soc@vger.kernel.org>,
	dri-devel@lists.freedesktop.org, a.hajda@samsung.com,
	Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Subject: Re: [PATCH] drm/exynos: Make exynos_drm_init() call late during the bootup
Date: Tue, 27 May 2014 22:02:30 +0900	[thread overview]
Message-ID: <53848CE6.4020707@samsung.com> (raw)
In-Reply-To: <CAHfPSqBoh=RmavEsJPwb8Mp5Or_M64smUk8NEpO8aAJm5RU0GQ@mail.gmail.com>

On 2014년 05월 26일 14:39, Naveen Krishna Ch wrote:
> Hello Everyone,
> 
> On 21 May 2014 21:16, Thierry Reding <thierry.reding@gmail.com> wrote:
>> On Wed, May 14, 2014 at 05:09:45PM +0530, Naveen Krishna Chatradhi wrote:
>>> exynos_drm_init() does probing of various drivers like dp_panel,
>>> hdmi, fimd, mixer, etc in an order and finally binds them together.
>>>
>>> Some of the drm devices (Eg: dp_panel) try to do regulator_get()
>>> and enable few supplies during their probe.
>>> Chances are that, these devices may get probed before the respective
>>> supply/PMIC is hooked.  In such cases, dp_panel would continue with
>>> "dummy regulator". Which is not what the system wants.
>>>
>>> Lets give the core connectivity and regulators modules some time
>>> to hookup the supplies before Exynos DRM devices comes into picture.
>>>
>>> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
>>> ---
>>> This change is proposed after
>>> 1. Discussing with I2C/SPI & DMA subsystem maintainers and Others
>>>    @ https://lkml.org/lkml/2014/5/9/333
>>>    Trying to change the I2C, SPI and DMA drivers as subsys_initcall()
>>>    Which was strictly opposed, as a flaw was found in DRM subsystem.
>>>
>>> 2. -EPROBE_DEFER won't work well with the current sequency of
>>>     platform_driver_register()s in exynos_drm_init()
>>
>> Then this is the problem that you need to fix. If the driver doesn't
>> handle -EPROBE_DEFER properly then that means the driver is broken. No
>> amount of initcall ordering can fix this for you.
> 
> We seem to have a problem with the probe sequencing and usage of _EPROBE_DEFER
> in DRM.  Component way of registration doesnt seem to fix everything.
> 
> Inki Dae,
> Is there any discussion or approach underway.
> Anyone working on this.

Hi,

I have just posted a patch series, [PATCH 0/2] drm/exynos: consider
deferred probe case, to resolve that issue. With this, it wouldn't need
your patch anymore.

Thanks,
Inki Dae

>>
>> Thierry
> 
> 
> 

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      reply	other threads:[~2014-05-27 13:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-14 11:39 [PATCH] drm/exynos: Make exynos_drm_init() call late during the bootup Naveen Krishna Chatradhi
2014-05-21  6:39 ` Naveen Krishna Ch
2014-05-21 15:46 ` Thierry Reding
2014-05-26  5:39   ` Naveen Krishna Ch
2014-05-27 13:02     ` Inki Dae [this message]

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