linux-kernel - Re: [PATCH] usb: host: xhci-plat: Iterate over parent nodes for finding quirks

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]

Date:   Mon, 6 Aug 2018 13:50:38 +0300
From:   Mathias Nyman <mathias.nyman@...ux.intel.com>
To:     Anurag Kumar Vulisha <anuragku@...inx.com>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: host: xhci-plat: Iterate over parent nodes for
 finding quirks

Hi,

Back from vacation

On 20.07.2018 18:39, Anurag Kumar Vulisha wrote:
> 
> Hi Mathias,
> 
> Thanks for providing your comments, please find my comments inline
> 
>>>
>>> -	if (device_property_read_bool(sysdev, "usb2-lpm-disable"))
>>> -		xhci->quirks |= XHCI_HW_LPM_DISABLE;
>>> +	/* Iterate over all parent nodes for finding quirks */
>>> +	for (tmpdev = &pdev->dev; tmpdev; tmpdev = tmpdev->parent) {
>>
>> Isn't sysdev at this point the topmost device that can have any of those device
>> properties set?
>> We could loop from &pdev->dev up to and including sysdev.
>>
>> It doesn't matter much but maybe avoid walking some extra parents.
>>> 
> I have seen some drivers ( like dwc3 host.c) which create a child dev, which is
> the pdev that is being passed to xhci_plat_probe(). So, sysdev may not be the
> topmost parent. There could be some properties which may be present in parent
> and may not be populated in the child. So, I made this change to search on all
> available parents for finding a valid property

Ok, lets keep it like you wrote it

> 
>>>
>>> -	if (device_property_read_bool(sysdev, "usb3-lpm-capable"))
>>> -		xhci->quirks |= XHCI_LPM_SUPPORT;
>>> +		if (device_property_read_bool(tmpdev, "usb2-lpm-disable"))
>>> +			xhci->quirks |= XHCI_HW_LPM_DISABLE;
>>>
>>> -	if (device_property_read_bool(&pdev->dev, "quirk-broken-port-ped"))
>>> -		xhci->quirks |= XHCI_BROKEN_PORT_PED;
>>> +		if (device_property_read_bool(tmpdev, "usb3-lpm-capable"))
>>> +			xhci->quirks |= XHCI_LPM_SUPPORT;
>>>
>>> -	/* imod_interval is the interrupt moderation value in nanoseconds. */
>>> -	xhci->imod_interval = 40000;
>>
>> Setting the default imod_interval could be moved before the for() loop
>>
> 
> I thought it would be better if everything related to imod_interval is in one place,
> so kept it as is. I can fix this in v2 if you suggest.

Default imod_interval needs to be set before the for loop to avoid overwriting a value
got from device property

So a v2 is needed

-Mathias