linux-kernel - Re: [PATCH] clk: qcom: sm8450: Enable retention for usb controller gdsc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9b8ad81f-28e1-471e-a8fc-9e64578aaf4f@oss.qualcomm.com>
Date: Wed, 11 Jun 2025 10:35:36 +0530
From: Krishna Kurapati <krishna.kurapati@....qualcomm.com>
To: Bjorn Andersson <andersson@...nel.org>
Cc: Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH] clk: qcom: sm8450: Enable retention for usb controller
 gdsc



On 6/11/2025 9:12 AM, Bjorn Andersson wrote:
> On Tue, Jun 10, 2025 at 02:52:53PM +0530, Krishna Kurapati wrote:
>> When USB controller enters runtime suspend while operating in host
>> mode, then wakeup because of cable disconnect or a button press of
>> a headset causes the following kind of errors:
>>
>> Error after button press on a connected headset :
>>
>> [  355.309260] usb 1-1: reset full-speed USB device number 2 using xhci-hcd
>> [  355.725844] usb 1-1: device not accepting address 2, error -108
>>
>> Error on removal of headset device from usb port:
>>
>> [  157.563136] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402
>> ,iova=0xd65504710, fsynr=0x100011, cbfrsynra=0x0, cb=6
>> [  157.574842] arm-smmu 15000000.iommu: FSR    = 00000402 [Format=2 TF],
>> SID=0x0
>> [  157.582181] arm-smmu 15000000.iommu: FSYNR0 = 00100011 [S1CBNDX=16 WNR
>> PLVL=1]
>> [  157.589610] xhci-hcd xhci-hcd.0.auto: WARNING: Host Controller Error
>> [  157.596197] xhci-hcd xhci-hcd.0.auto: WARNING: Host Controller Error
>>
>> Enabling retention on usb controller GDSC fixes the above issues.
>>
>> Signed-off-by: Krishna Kurapati <krishna.kurapati@....qualcomm.com>
>> ---
>>
>> Note:
>> The above mentioned issues pop up after I enabled runtime suspend after
>> applying [1].
>> [1]: https://lore.kernel.org/all/20250610091357.2983085-1-krishna.kurapati@oss.qualcomm.com/
>>
> 
> It makes sense that the BCR issue appears after the flattening of dwc3,
> but why would the suspend issue pop up?
> 
> The change matches what we do on many other platforms, but I've been
> hoping we either could drop the retention or clearly document why it's
> needed - so that we know if this should be on all or none of the SoCs.
> 

Sure, will try to root cause why we are seeing issues during suspend (on 
sm8450) and come up with another patch.

But I remember on sc7280-herobrine (and IIRC while testing multiport on 
sa8295), when gdsc was not in retention, after entering suspend, we 
would see a disconnect and reconnect of connected peripherals during 
resume (probably because controller was in off state during suspend). 
When I tested with RET_ON in sc7280, I see the re-enumeration after 
resume never popped up.

Regards,
Krishna,

> Regards,
> Bjorn
> 
>>   drivers/clk/qcom/gcc-sm8450.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/clk/qcom/gcc-sm8450.c b/drivers/clk/qcom/gcc-sm8450.c
>> index 65d7d52bce03..f94da4a1c921 100644
>> --- a/drivers/clk/qcom/gcc-sm8450.c
>> +++ b/drivers/clk/qcom/gcc-sm8450.c
>> @@ -3141,7 +3141,7 @@ static struct gdsc usb30_prim_gdsc = {
>>   	.pd = {
>>   		.name = "usb30_prim_gdsc",
>>   	},
>> -	.pwrsts = PWRSTS_OFF_ON,
>> +	.pwrsts = PWRSTS_RET_ON,
>>   };
>>   
>>   static struct clk_regmap *gcc_sm8450_clocks[] = {
>> -- 
>> 2.34.1
>>