linux-kernel - Re: [PATCH 0/4] media: platform: Add Aspeed Video Engine driver

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Date:   Fri, 31 Aug 2018 10:56:31 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Eddie James <eajames@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org
Cc:     linux-media@...r.kernel.org, linux-aspeed@...ts.ozlabs.org,
        openbmc@...ts.ozlabs.org, andrew@...id.au, mchehab@...nel.org,
        joel@....id.au, robh+dt@...nel.org, mark.rutland@....com,
        devicetree@...r.kernel.org, linux-clk@...r.kernel.org,
        mturquette@...libre.com, linux-arm-kernel@...ts.infradead.org,
        Eddie James <eajames@...ux.vnet.ibm.com>
Subject: Re: [PATCH 0/4] media: platform: Add Aspeed Video Engine driver

Quoting Eddie James (2018-08-29 14:09:29)
> The Video Engine (VE) embedded in the Aspeed AST2400 and AST2500 SOCs
> can capture and compress video data from digital or analog sources. With
> the Aspeed chip acting as a service processor, the Video Engine can
> capture the host processor graphics output.
> 
> This series adds a V4L2 driver for the VE, providing a read() interface
> only. The driver triggers the hardware to capture the host graphics output
> and compress it to JPEG format.
> 
> Testing on an AST2500 determined that the videobuf/streaming/mmap interface
> was significantly slower than the simple read() interface, so I have not
> included the streaming part.
> 
> It's also possible to use an automatic mode for the VE such that
> re-triggering the HW every frame isn't necessary. However this wasn't
> reliable on the AST2400, and probably used more CPU anyway due to excessive
> interrupts. It was approximately 15% faster.
> 
> The series also adds the necessary parent clock definitions to the Aspeed
> clock driver, with both a mux and clock divider.

Please let me know your merge strategy here. I can ack the clk patches
because they look fine from high-level clk driver perspective (maybe
Joel can take a closer look) or I can merge the patches into clk-next
and get them into next release while the video driver gets reviewed.