[PATCH] drm/exynos: Make exynos_drm_init() call late during the bootup

Inki Dae inki.dae at samsung.com
Tue May 27 06:02:30 PDT 2014

On 2014년 05월 26일 14:39, Naveen Krishna Ch wrote:
> Hello Everyone,
> On 21 May 2014 21:16, Thierry Reding <thierry.reding at 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 at 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.


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.

Inki Dae

>> Thierry

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