linux-kernel - Re: [PATCH 01/36] drm/fourcc: Add 2 plane YCbCr 10bit format support

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Date:   Tue, 24 Sep 2019 14:47:33 +0800
From:   "sandy.huang" <hjc@...k-chips.com>
To:     Ville Syrjälä <ville.syrjala@...ux.intel.com>
Cc:     dri-devel@...ts.freedesktop.org,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/36] drm/fourcc: Add 2 plane YCbCr 10bit format support

在 2019/9/24 上午2:30, Ville Syrjälä 写道:
> On Mon, Sep 23, 2019 at 06:05:22AM -0700, sandy.huang wrote:
>> 在 2019/9/23 上午5:53, Ville Syrjälä 写道:
>>> On Mon, Sep 23, 2019 at 08:38:50PM +0800, Sandy Huang wrote:
>>>> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
>>>> index 3feeaa3..5fe89e9 100644
>>>> --- a/include/uapi/drm/drm_fourcc.h
>>>> +++ b/include/uapi/drm/drm_fourcc.h
>>>> @@ -266,6 +266,21 @@ extern "C" {
>>>>    #define DRM_FORMAT_P016		fourcc_code('P', '0', '1', '6') /* 2x2 subsampled Cr:Cb plane 16 bits per channel */
>>>>    
>>>>    /*
>>>> + * 2 plane YCbCr 10bit
>>>> + * index 0 = Y plane, [9:0] Y
>>>> + * index 1 = Cr:Cb plane, [19:0] Cr:Cb little endian
>>>> + * or
>>>> + * index 1 = Cb:Cr plane, [19:0] Cb:Cr little endian
>>> What does "little endian" even mean for these?
>> It's Inherited from the following define, the difference is 8bit and 10bit.
>> /*
>>    * 2 plane YCbCr
>>    * index 0 = Y plane, [7:0] Y
>>    * index 1 = Cr:Cb plane, [15:0] Cr:Cb little endian
>>    * or
>>    * index 1 = Cb:Cr plane, [15:0] Cb:Cr little endian
>>    */
>> #define DRM_FORMAT_NV12        fourcc_code('N', 'V', '1', '2') /* 2x2
>> subsampled Cr:Cb plane */
>> #define DRM_FORMAT_NV21        fourcc_code('N', 'V', '2', '1') /* 2x2
>> subsampled Cb:Cr plane */
>> #define DRM_FORMAT_NV16        fourcc_code('N', 'V', '1', '6') /* 2x1
>> subsampled Cr:Cb plane */
>> #define DRM_FORMAT_NV61        fourcc_code('N', 'V', '6', '1') /* 2x1
>> subsampled Cb:Cr plane */
>> #define DRM_FORMAT_NV24        fourcc_code('N', 'V', '2', '4') /*
>> non-subsampled Cr:Cb plane */
>> #define DRM_FORMAT_NV42        fourcc_code('N', 'V', '4',
> Something not aligned to bytes can't have its endianness defined the
> same way as these. Just doesn't make sense.

Get it ,thanks.

>>
>>
>>>> + */
>>>> +
>>>> +#define DRM_FORMAT_NV12_10	fourcc_code('N', 'A', '1', '2') /* 2x2 subsampled Cr:Cb plane */
>>>> +#define DRM_FORMAT_NV21_10	fourcc_code('N', 'A', '2', '1') /* 2x2 subsampled Cb:Cr plane */
>>>> +#define DRM_FORMAT_NV16_10	fourcc_code('N', 'A', '1', '6') /* 2x1 subsampled Cr:Cb plane */
>>>> +#define DRM_FORMAT_NV61_10	fourcc_code('N', 'A', '6', '1') /* 2x1 subsampled Cb:Cr plane */
>>>> +#define DRM_FORMAT_NV24_10	fourcc_code('N', 'A', '2', '4') /* non-subsampled Cr:Cb plane */
>>>> +#define DRM_FORMAT_NV42_10	fourcc_code('N', 'A', '4', '2') /* non-subsampled Cb:Cr plane */
>>>> +
>>>> +/*
>>>>     * 3 plane YCbCr
>>>>     * index 0: Y plane, [7:0] Y
>>>>     * index 1: Cb plane, [7:0] Cb
>>>> -- 
>>>> 2.7.4
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> dri-devel mailing list
>>>> dri-devel@...ts.freedesktop.org
>>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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