Linux USB
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From: Elson Serrao <elson.serrao@oss.qualcomm.com>
To: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>,
	Bjorn Andersson <andersson@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Rob Herring <robh@kernel.org>
Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Peter Chen <peter.chen@kernel.org>
Subject: Re: [PATCH v7 6/8] usb: misc: qcom_eud: add role-based EUD control
Date: Wed, 9 Sep 2026 18:37:14 -0700	[thread overview]
Message-ID: <2ea2d992-d14d-4b26-91f3-c36a87acf82a@oss.qualcomm.com> (raw)
In-Reply-To: <f23595ab-e0ef-40d8-998b-4cb0426ec166@oss.qualcomm.com>



On 9/1/2026 4:36 AM, Konrad Dybcio wrote:
> On 8/31/26 5:01 AM, Elson Serrao wrote:
>> EUD functions by presenting itself as a USB device to the host PC and is
>> therefore only applicable when the port operates in device role. Keeping
>> EUD enabled in other roles provides no benefit and unnecessarily keeps
>> the associated PHY resources enabled. Furthermore, enabling EUD in host
>> role can cause the USB controller to misbehave because the EUD hub
>> supports only a single upstream-facing port.
> 
> [...]
> 
>>  	struct eud_chip *chip = dev_get_drvdata(dev);
>> +	struct eud_path *path;
>>  	bool enable;
>>  	int ret;
>>  
>>  	if (kstrtobool(buf, &enable))
>>  		return -EINVAL;
>>  
>> +	guard(mutex)(&chip->state_lock);
> 
> GPT suggests port_store() should also take this lock.. I think that's
> a valid concern
> 
Thanks for the review, and apologies for the delayed response.

I'll address this as well as the other relevant feedback from Sashiko in v8.

Thanks,
Elson

  reply	other threads:[~2026-09-10  1:37 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-31  3:01 [PATCH v7 0/8] Improve Qualcomm EUD driver and platform support Elson Serrao
2026-08-31  3:01 ` [PATCH v7 1/8] dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing Elson Serrao
2026-08-31 22:39   ` Bjorn Andersson
2026-08-31  3:01 ` [PATCH v7 2/8] usb: misc: qcom_eud: add sysfs attribute for port selection Elson Serrao
2026-08-31  3:01 ` [PATCH v7 3/8] usb: misc: qcom_eud: add per-path High-Speed PHY control Elson Serrao
2026-08-31  3:01 ` [PATCH v7 4/8] usb: misc: qcom_eud: add per-path role switch support Elson Serrao
2026-08-31  3:01 ` [PATCH v7 5/8] usb: misc: qcom_eud: improve enable_store API Elson Serrao
2026-08-31  3:01 ` [PATCH v7 6/8] usb: misc: qcom_eud: add role-based EUD control Elson Serrao
2026-09-01 11:36   ` Konrad Dybcio
2026-09-10  1:37     ` Elson Serrao [this message]
2026-08-31  3:01 ` [PATCH v7 7/8] usb: misc: qcom_eud: fix virtual attach/detach event handling Elson Serrao
2026-08-31  3:01 ` [PATCH v7 8/8] arm64: dts: qcom: kodiak: Desribe EUD UTMI routing and connector mapping Elson Serrao

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