From: Rob Herring <robh@kernel.org>
To: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
Cc: gregkh@linuxfoundation.org, mark.rutland@arm.com,
balbi@kernel.org, v.anuragkumar@gmail.com,
linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: dwc3: core: Add quirk for enabling AutoRetry feature in the controller
Date: Wed, 25 Jul 2018 14:03:25 -0600 [thread overview]
Message-ID: <20180725200325.GA21007@rob-hp-laptop> (raw)
In-Reply-To: <1532168920-3269-1-git-send-email-anurag.kumar.vulisha@xilinx.com>
On Sat, Jul 21, 2018 at 03:58:40PM +0530, Anurag Kumar Vulisha wrote:
> By default when core sees any transaction error(CRC or overflow)
> it replies with terminating retry ACK (Retry=1 and Nump == 0).
> Enabling this Auto Retry feature in controller, on seeing any
> transaction errors makes the core to send an non-terminating ACK
> transaction packet (that is, ACK TP with Retry=1 and Nump != 0).
> Doing so will give controller a chance to recover from the error
> condition.
>
> Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
> ---
> Documentation/devicetree/bindings/usb/dwc3.txt | 5 +++++
> drivers/usb/dwc3/core.c | 16 ++++++++++++++++
> drivers/usb/dwc3/core.h | 6 ++++++
> 3 files changed, 27 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
> index 7f13ebe..2ba2bc2 100644
> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
> @@ -94,6 +94,11 @@ Optional properties:
> this and tx-thr-num-pkt-prd to a valid, non-zero value
> 1-16 (DWC_usb31 programming guide section 1.2.3) to
> enable periodic ESS TX threshold.
> + - snps,enable_auto_retry: Set to enable Auto retry Feature to make the
s/_/-/
> + controller operating in Host mode on seeing transaction
> + errors(CRC errors or internal overrun scenerios) on IN
> + transfers to reply to the device with a non-terminating
> + retry ACK (i.e, an ACK TP with Retry=1 & Nump != 0)
Seems like the property is unnecessary. When would you not want this
retry behavior? Why not just enable unconditionally in the driver?
Rob
next prev parent reply other threads:[~2018-07-25 20:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-21 10:28 [PATCH] usb: dwc3: core: Add quirk for enabling AutoRetry feature in the controller Anurag Kumar Vulisha
2018-07-25 20:03 ` Rob Herring [this message]
2018-07-26 2:35 ` Anurag Kumar Vulisha
2018-07-26 11:14 ` Felipe Balbi
2018-07-27 7:29 ` Anurag Kumar Vulisha
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