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Message-ID: <Yml16DvnUR/tJSCO@kroah.com>
Date: Wed, 27 Apr 2022 18:57:12 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Frank Li <Frank.Li@....com>
Cc: peter.chen@...nel.org, pawell@...ence.com, rogerq@...nel.org,
a-govindraju@...com, linux-usb@...r.kernel.org, jun.li@....com,
lznuaa@...il.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 1/1] usb: cdns3: allocate TX FIFO size according to
composite EP number
On Wed, Apr 27, 2022 at 11:35:25AM -0500, Frank Li wrote:
> Some devices have USB compositions which may require multiple endpoints.
> To get better performance, need bigger CDNS3_EP_BUF_SIZE.
>
> But bigger CDNS3_EP_BUF_SIZE may exceed total hardware FIFO size when
> multiple endpoints.
>
> By introducing the check_config() callback, calculate CDNS3_EP_BUF_SIZE.
>
> Move CDNS3_EP_BUF_SIZE into cnds3_device: ep_buf_size
> Combine CDNS3_EP_ISO_SS_BURST and CDNS3_EP_ISO_HS_MULT into
> ecnds3_device:ep_iso_burst
>
> Using a simple algorithm to calculate ep_buf_size.
> ep_buf_size = ep_iso_burst = (onchip_buffers - 2k) / (number of IN EP +
> 1).
>
> Test at 8qxp:
>
> Gadget ep_buf_size
>
> RNDIS: 5
> RNDIS+ACM: 3
> Mass Storage + NCM + ACM 2
>
> Previous CDNS3_EP_BUF_SIZE is 4, RNDIS + ACM will be failure because
> exceed FIFO memory.
>
> Signed-off-by: Frank Li <Frank.Li@....com>
> ---
> Change from v1 to v2:
> Add safe check for mult, buffering and maxburst
that's nice, but this is v8, not v2?
confused,
greg k-h
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