Re: [PATCH v6] usb: gadget: storage: make FSG_NUM_BUFFERS variablesize

[Michal Nazarewicz]

On Fri, 19 Aug 2011 21:21:27 +0200, Per Forlin <per.forlin@xxxxxxxxxx>  
wrote:
> FSG_NUM_BUFFERS is set to 2 as default.
> Usually 2 buffers are enough to establish a good buffering pipeline.
> The number may be increased in order to compensate a for bursty VFS
> behaviour.
>
> Here follows a description of system that may require more than
> 2 buffers.
>  * CPU ondemand governor active
>  * latency cost for wake up and/or frequency change
>  * DMA for IO
>
> Use case description.
>  * Data transfer from MMC via VFS to USB.
>  * DMA shuffles data from MMC and to USB.
>  * The CPU wakes up every now and then to pass data in and out from VFS,
>    which cause the bursty VFS behaviour.

> Signed-off-by: Per Forlin <per.forlin@xxxxxxxxxx>

Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>

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