Sender: Larry Finger <larry.finger@gmail.com>
Message-ID: <18be9b45-e7c1-9f81-afeb-3e0d4cfe5f73@lwfinger.net>
Date:   Mon, 27 Feb 2023 21:57:24 -0600
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Subject: Re: [RFC 0/6] pcmcia: separate 16-bit support from cardbus
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To:     Arnd Bergmann <arnd@arndb.de>, Arnd Bergmann <arnd@kernel.org>,
        Dominik Brodowski <linux@dominikbrodowski.net>,
        linux-kernel@vger.kernel.org
Cc:     Bjorn Helgaas <bhelgaas@google.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Hartley Sweeten <hsweeten@visionengravers.com>,
        Ian Abbott <abbotti@mev.co.uk>,
        Jakub Kicinski <kuba@kernel.org>,
        Kevin Cernekee <cernekee@gmail.com>,
        Lukas Wunner <lukas@wunner.de>,
        Manuel Lauss <manuel.lauss@gmail.com>,
        Oliver Hartkopp <socketcan@hartkopp.net>,
        Olof Johansson <olof@lixom.net>,
        Robert Jarzmik <robert.jarzmik@free.fr>,
        YOKOTA Hiroshi <yokota@netlab.is.tsukuba.ac.jp>,
        bcm-kernel-feedback-list@broadcom.com,
        linux-arm-kernel@lists.infradead.org, linux-can@vger.kernel.org,
        linux-mips@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-wireless@vger.kernel.org, Netdev <netdev@vger.kernel.org>
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From:   Larry Finger <Larry.Finger@lwfinger.net>
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On 2/27/23 15:30, Arnd Bergmann wrote:
> On Mon, Feb 27, 2023, at 22:09, Larry Finger wrote:
>> On 2/27/23 14:38, Arnd Bergmann wrote:
>>> Is this the Cardbus or the PCMCIA version of the BCM4306 device? As far
>>> as I understand this particular chip can be wired up either way inside
>>> of the card, and the PowerBook G4 supports both types of devices.
>>>
>>> If it's the PCMCIA version, then dropping support for it was the idea
>>> of the patch series that we can debate, but if it was the Cardbus version
>>> that broke, then this was likely a bug I introduced by accident.
>>
>> The BCM4306 is internal, and wired directly to the PCI bus. My understanding is
>> that the BCM4318 is a cardbus device. It definitely shows up in an lspci scan.
> 
> Ah right, I got confused because I had googled for BCM4306 for too long
> trying to find out whether that might be used in combination with the
> BCM63xx SoC support that patch 1 removed.
> 
> BCM4318 should definitely keep working after my series. My best guess
> is that the problem is that I introduced an unnecessary dependency
> between CONFIG_CARDBUS and CONFIG_PCI_HOTPLUG, so you'd need to
> either undo the dependency or enable both in the local config.
> 
> If it's not that, then it's a bug in my changes that needs to be
> fixed before they can be considered for integration. As long as
> we are still debating whether the series makes sense at all,
> I'm not worried about this.

Arnd,

It was a configuration problem. In the .config obtained by installing your 
patches, and doing a make, CONFIG_CARDBUS was not mentioned, and 
CONFIG_PCI_HOTPLUG was not selected. When I deleted the reference to the latter, 
did a make, and set ..._HOTPLUG, I got CONFIG+CARDBUS set to "m", and the yenta 
modules were built. This version sees the BCM4318 in the lspci scan, and the 
interface works. Your patches are OK.

I am not sure how to warn people about the configuration change possible 
breaking things.

Larry