From: Florian Fainelli <f.fainelli@gmail.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Cooper <alcooperx@gmail.com>,
linux-kernel@vger.kernel.org,
Alan Stern <stern@rowland.harvard.edu>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
bcm-kernel-feedback-list@broadcom.com,
devicetree@vger.kernel.org, Krzysztof Kozlowski <krzk@kernel.org>,
linux-usb@vger.kernel.org,
Mathias Nyman <mathias.nyman@intel.com>,
Rob Herring <robh+dt@kernel.org>,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH v10 1/5] usb: xhci: Change the XHCI link order in the Makefile
Date: Wed, 13 May 2020 09:31:11 -0700 [thread overview]
Message-ID: <38ff034d-a84c-2309-a8d5-f344930d9a31@gmail.com> (raw)
In-Reply-To: <20200513162723.GF1362525@kroah.com>
On 5/13/2020 9:27 AM, Greg Kroah-Hartman wrote:
> On Wed, May 13, 2020 at 08:08:07AM -0700, Florian Fainelli wrote:
>>
>>
>> On 5/13/2020 5:26 AM, Greg Kroah-Hartman wrote:
>>> On Tue, May 12, 2020 at 11:00:15AM -0400, Al Cooper wrote:
>>>> Some BRCMSTB USB chips have an XHCI, EHCI and OHCI controller
>>>> on the same port where XHCI handles 3.0 devices, EHCI handles 2.0
>>>> devices and OHCI handles <2.0 devices. Currently the Makefile
>>>> has XHCI linking at the bottom which will result in the XHIC driver
>>>> initalizing after the EHCI and OHCI drivers and any installed 3.0
>>>> device will be seen as a 2.0 device. Moving the XHCI linking
>>>> above the EHCI and OHCI linking fixes the issue.
>>>
>>> What happens if all of these are modules and they are loaded in a
>>> different order? This makefile change will not help with that, you need
>>> to have logic in the code in order to properly coordinate this type of
>>> mess, sorry.
>>
>> I believe we should be using module soft dependencies to instruct the
>> module loaders to load the modules in the correct order, so something
>> like this would do (not tested) for xhci-plat-hcd.c:
>>
>> MODULE_SOFTDEP("post: ehci-hcd ohci-hcd");
>>
>> and I am not sure whether we need to add the opposite for ehci-hcd and
>> ohci-hcd:
>>
>> MODULE_SOFTDEP("pre: xhci-plat-hcd");
>
> That's a nice start, but what happens if that isn't honored? This
> really needs to work properly for any order as you never can guarantee
> module/driver loading order in a system of modules.
I also suggested that device links may help, though I am not sure. What
do you suggest to be done?
--
Florian
next prev parent reply other threads:[~2020-05-13 16:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-12 15:00 [PATCH v10 0/5] Add XHCI, EHCI and OHCI support for Broadcom STB SoS's Al Cooper
2020-05-12 15:00 ` [PATCH v10 1/5] usb: xhci: Change the XHCI link order in the Makefile Al Cooper
2020-05-13 12:26 ` Greg Kroah-Hartman
2020-05-13 15:08 ` Florian Fainelli
2020-05-13 15:26 ` Andy Shevchenko
2020-05-13 15:28 ` Florian Fainelli
2020-05-13 16:27 ` Greg Kroah-Hartman
2020-05-13 16:31 ` Florian Fainelli [this message]
2020-05-13 17:05 ` Greg Kroah-Hartman
2020-05-13 17:39 ` Alan Stern
2020-05-13 17:46 ` Florian Fainelli
2020-05-13 19:42 ` Alan Cooper
2020-05-20 17:29 ` Alan Cooper
2020-05-21 6:09 ` Greg Kroah-Hartman
2020-05-21 15:37 ` Florian Fainelli
2020-05-12 15:00 ` [PATCH v10 2/5] dt-bindings: Add Broadcom STB USB support Al Cooper
2020-05-12 15:00 ` [PATCH v10 3/5] usb: xhci: xhci-plat: Add support for Broadcom STB SoC's Al Cooper
2020-05-12 15:00 ` [PATCH v10 4/5] usb: ehci: Add new EHCI driver " Al Cooper
2020-05-12 15:00 ` [PATCH v10 5/5] usb: host: Add ability to build new Broadcom STB USB drivers Al Cooper
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