linux-kernel - Re: [PATCH v11 08/16] drm/mediatek: De-commonize disp_aal/disp_gamma gamma

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Message-ID: <7d50a061-dd73-40e4-af7d-ac8252bcea25@collabora.com>
Date:   Wed, 25 Oct 2023 12:43:53 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     CK Hu (胡俊光) <ck.hu@...iatek.com>,
        "chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "wenst@...omium.org" <wenst@...omium.org>,
        "kernel@...labora.com" <kernel@...labora.com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "ehristev@...labora.com" <ehristev@...labora.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "nfraprado@...labora.com" <nfraprado@...labora.com>
Subject: Re: [PATCH v11 08/16] drm/mediatek: De-commonize disp_aal/disp_gamma
 gamma_set functions

Il 13/10/23 06:07, CK Hu (胡俊光) ha scritto:
> Hi, Angelo:
> 
> On Thu, 2023-10-12 at 11:57 +0200, AngeloGioacchino Del Regno wrote:
>> In preparation for adding a 12-bits gamma support for the DISP_GAMMA
>> IP, remove the mtk_gamma_set_common() function and move the relevant
>> bits in mtk_gamma_set() for DISP_GAMMA and mtk_aal_gamma_set() for
>> DISP_AAL: since the latter has no more support for gamma manipulation
>> (being moved to a different IP) in newer revisions, those functions
>> are about to diverge and it makes no sense to keep a common one (with
>> all the complications of passing common data and making exclusions
>> for device driver data) for just a few bits.
>>
>> This commit brings no functional changes.
> 
> Reviewed-by: CK Hu <ck.hu@...iatek.com>
> 
>>
>> Signed-off-by: AngeloGioacchino Del Regno <
>> angelogioacchino.delregno@...labora.com>

..snip..

>> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
>> b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
>> index 81c04518a5eb..0929f8830d6d 100644
>> --- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
>> +++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
>> @@ -69,41 +69,28 @@ unsigned int mtk_gamma_get_lut_size(struct device
>> *dev)
>>   	return 0;
>>   }
>>   
>> -void mtk_gamma_set_common(struct device *dev, void __iomem *regs,
>> struct drm_crtc_state *state)
>> +void mtk_gamma_set(struct device *dev, struct drm_crtc_state *state)
>>   {

..snip..

>>   
>> -	cfg_val = readl(regs + DISP_GAMMA_CFG);
>> +	cfg_val = readl(gamma->regs + DISP_GAMMA_CFG);
>>   
>>   	/* Enable the gamma table */
>>   	cfg_val |= FIELD_PREP(GAMMA_LUT_EN, 1);
>>   
>> -	writel(cfg_val, regs + DISP_GAMMA_CFG);
>> -}
>> -
>> -void mtk_gamma_set(struct device *dev, struct drm_crtc_state *state)
>> -{
>> -	struct mtk_disp_gamma *gamma = dev_get_drvdata(dev);
>> -
>> -	mtk_gamma_set_common(dev, gamma->regs, state);
>> +	writel(cfg_val, gamma->regs + DISP_GAMMA_CFG);

Hello CK,

something went wrong while you applied this patch: this writel became a readl,
breaking mtk_disp_gamma entirely. Please check:

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/mediatek/mtk_disp_gamma.c?h=next-20231025&id=a6b39cd248f3321dbf066f95f95a9841f891229e

Thanks,
Angelo