linux-kernel - Re: [PATCH] usb: dwc2: Skip clock gating on Samsung SoCs

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Message-ID: <6fb5313e-b2c0-7b3e-84f7-6333216f4292@synopsys.com>
Date:   Fri, 16 Jul 2021 09:07:25 +0000
From:   Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Felipe Balbi <felipe.balbi@...ux.intel.com>,
        Artur Petrosyan <Arthur.Petrosyan@...opsys.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: Re: [PATCH] usb: dwc2: Skip clock gating on Samsung SoCs

Hi Krzysztof,

On 7/16/2021 12:10 PM, Krzysztof Kozlowski wrote:
> On 16/07/2021 07:01, Marek Szyprowski wrote:
>> Commit 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr
>> function.") changed the way the driver handles power down modes in a such
>> way that it uses clock gating when no other power down mode is available.
>>
>> This however doesn't work well on the DWC2 implementation used on the
>> Samsung SoCs. When a clock gating is enabled, system hangs. It looks that
>> the proper clock gating requires some additional glue code in the shared
>> USB2 PHY and/or Samsung glue code for the DWC2. To restore driver
>> operation on the Samsung SoCs simply skip enabling clock gating mode
>> until one finds what is really needed to make it working reliably.
>>
>> Fixes: 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr function.")
>> Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
>> ---
>>   drivers/usb/dwc2/core.h      | 4 ++++
>>   drivers/usb/dwc2/core_intr.c | 3 ++-
>>   drivers/usb/dwc2/hcd.c       | 6 ++++--
>>   drivers/usb/dwc2/params.c    | 1 +
>>   4 files changed, 11 insertions(+), 3 deletions(-)
>>
> 
> 
> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
> 
What mean your "Acked-by" tag? Do you want to mention that this commit 
"Tested-by" or "Reviewed-by" by you?

Thanks,
Minas

> 
> Best regards,
> Krzysztof
>