1 .. SPDX-License-Identifier: GPL-2.0 1 .. SPDX-License-Identifier: GPL-2.0
2 2
3 .. include:: <isonum.txt> 3 .. include:: <isonum.txt>
4 4
5 ASPEED video driver 5 ASPEED video driver
6 =================== 6 ===================
7 7
8 ASPEED Video Engine found on AST2400/2500/2600 8 ASPEED Video Engine found on AST2400/2500/2600 SoC supports high performance
9 video compressions with a wide range of video 9 video compressions with a wide range of video quality and compression ratio
10 options. The adopted compressing algorithm is 10 options. The adopted compressing algorithm is a modified JPEG algorithm.
11 11
12 There are 2 types of compressions in this IP. 12 There are 2 types of compressions in this IP.
13 13
14 * JPEG JFIF standard mode: for single frame an 14 * JPEG JFIF standard mode: for single frame and management compression
15 * ASPEED proprietary mode: for multi-frame and 15 * ASPEED proprietary mode: for multi-frame and differential compression.
16 Support 2-pass (high quality) video compress 16 Support 2-pass (high quality) video compression scheme (Patent pending by
17 ASPEED). Provide visually lossless video com 17 ASPEED). Provide visually lossless video compression quality or to reduce
18 the network average loading under intranet K 18 the network average loading under intranet KVM applications.
19 19
20 VIDIOC_S_FMT can be used to choose which forma 20 VIDIOC_S_FMT can be used to choose which format you want. V4L2_PIX_FMT_JPEG
21 stands for JPEG JFIF standard mode; V4L2_PIX_F 21 stands for JPEG JFIF standard mode; V4L2_PIX_FMT_AJPG stands for ASPEED
22 proprietary mode. 22 proprietary mode.
23 23
24 More details on the ASPEED video hardware oper 24 More details on the ASPEED video hardware operations can be found in
25 *chapter 6.2.16 KVM Video Driver* of SDK_User_ 25 *chapter 6.2.16 KVM Video Driver* of SDK_User_Guide which available on
26 `github <https://github.com/AspeedTech-BMC/ope 26 `github <https://github.com/AspeedTech-BMC/openbmc/releases/>`__.
27 27
28 The ASPEED video driver implements the followi 28 The ASPEED video driver implements the following driver-specific control:
29 29
30 ``V4L2_CID_ASPEED_HQ_MODE`` 30 ``V4L2_CID_ASPEED_HQ_MODE``
31 --------------------------- 31 ---------------------------
32 Enable/Disable ASPEED's High quality mode. 32 Enable/Disable ASPEED's High quality mode. This is a private control
33 that can be used to enable high quality fo 33 that can be used to enable high quality for aspeed proprietary mode.
34 34
35 .. flat-table:: 35 .. flat-table::
36 :header-rows: 0 36 :header-rows: 0
37 :stub-columns: 0 37 :stub-columns: 0
38 :widths: 1 4 38 :widths: 1 4
39 39
40 * - ``(0)`` 40 * - ``(0)``
41 - ASPEED HQ mode is disabled. 41 - ASPEED HQ mode is disabled.
42 * - ``(1)`` 42 * - ``(1)``
43 - ASPEED HQ mode is enabled. 43 - ASPEED HQ mode is enabled.
44 44
45 ``V4L2_CID_ASPEED_HQ_JPEG_QUALITY`` 45 ``V4L2_CID_ASPEED_HQ_JPEG_QUALITY``
46 ----------------------------------- 46 -----------------------------------
47 Define the quality of ASPEED's High qualit 47 Define the quality of ASPEED's High quality mode. This is a private control
48 that can be used to decide compression qua 48 that can be used to decide compression quality if High quality mode enabled
49 . Higher the value, better the quality and 49 . Higher the value, better the quality and bigger the size.
50 50
51 .. flat-table:: 51 .. flat-table::
52 :header-rows: 0 52 :header-rows: 0
53 :stub-columns: 0 53 :stub-columns: 0
54 :widths: 1 4 54 :widths: 1 4
55 55
56 * - ``(1)`` 56 * - ``(1)``
57 - minimum 57 - minimum
58 * - ``(12)`` 58 * - ``(12)``
59 - maximum 59 - maximum
60 * - ``(1)`` 60 * - ``(1)``
61 - step 61 - step
62 * - ``(1)`` 62 * - ``(1)``
63 - default 63 - default
64 64
65 **Copyright** |copy| 2022 ASPEED Technology In 65 **Copyright** |copy| 2022 ASPEED Technology Inc.
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