linux-kernel - Re: [PATCH] drm/exynos: don't use HW trigger for Exynos5420/5422/5800

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Message-id: <575E0E89.40400@samsung.com>
Date:	Mon, 13 Jun 2016 10:38:17 +0900
From:	Inki Dae <inki.dae@...sung.com>
To:	Javier Martinez Canillas <javier@...hile0.org>
Cc:	Javier Martinez Canillas <javier@....samsung.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Marc Zyngier <marc.zyngier@....com>,
	Kukjin Kim <kgene@...nel.org>,
	Seung-Woo Kim <sw0312.kim@...sung.com>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	David Airlie <airlied@...ux.ie>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] drm/exynos: don't use HW trigger for Exynos5420/5422/5800



2016년 06월 10일 09:24에 Javier Martinez Canillas 이(가) 쓴 글:
> Hello Inki,
> 
> On Thu, Jun 9, 2016 at 6:35 PM, Inki Dae <inki.dae@...sung.com> wrote:
> 
> [snip]
> 
>>> I know that removing .trg_type is enough but I also removed those lines
>>> because the fields are not used if .trg_type != I80_HW_TRG. So there is
>>> no point to leave a set for unused fields.
>>>
>>> We can latter add those one HW trigger support is fixed for Exynos5420.
>>>
>>
>> As of now, I can merge it but I think it would be not reasonable solution because potential problem still exists even we use SW trigger mode in default - ie., in case of using HW trigger mode at bootloader, same problem would happen as long as we don't support PSR mode support.
>>
> 
> Yes, I understand that the problem will show again if the bootloader
> uses HW trigger mode and that we need proper Panel Self Refresh
> support but I think that's a separate issue. That's why I said that
> those can be addressed for v4.8 but revert to SW trigger for v4.7 as a
> short term fix for the regression.
> 
> In other words, enabling HW trigger mode breaks the display for the
> Exynos5420 and Exynos5800 Peach Pi Chromebooks with the shipped
> bootloaders (which are probably the most popular Exynos5 devices with
> display and mainline support so is likely to affect users).

I thought to add PSR support somehow but put me other things to trouble.
Anyway, we could support it later so picked it up.

Thanks,
Inki Dae

> 
> Best regards,
> Javier
> 
> 
>