RE: [PATCH net-next v9 5/9] net: txgbe: Add SFP module identify

["Jiawen Wu" <jiawenwu@trustnetic.com>]

On Tuesday, May 30, 2023 4:41 PM, Jiawen Wu wrote:
> On Monday, May 29, 2023 10:06 AM, Jiawen Wu wrote:
> > On Friday, May 26, 2023 7:37 PM, Russell King (Oracle) wrote:
> > > On Fri, May 26, 2023 at 07:30:45PM +0800, kernel test robot wrote:
> > > > Kconfig warnings: (for reference only)
> > > >    WARNING: unmet direct dependencies detected for I2C_DESIGNWARE_PLATFORM
> > > >    Depends on [n]: I2C [=n] && HAS_IOMEM [=y] && (ACPI && COMMON_CLK [=y] || !ACPI)
> > > >    Selected by [y]:
> > > >    - TXGBE [=y] && NETDEVICES [=y] && ETHERNET [=y] && NET_VENDOR_WANGXUN [=y] && PCI [=y]
> > > >    WARNING: unmet direct dependencies detected for SFP
> > > >    Depends on [n]: NETDEVICES [=y] && PHYLIB [=y] && I2C [=n] && PHYLINK [=y] && (HWMON [=n] || HWMON [=n]=n)
> > > >    Selected by [y]:
> > > >    - TXGBE [=y] && NETDEVICES [=y] && ETHERNET [=y] && NET_VENDOR_WANGXUN [=y] && PCI [=y]
> > >
> > > ... and is basically caused by "select SFP". No. Do not do this unless
> > > you look at the dependencies for SFP and ensure that those are also
> > > satisfied - because if you don't you create messes like the above
> > > build errors.
> >
> > So how do I make sure that the module I need compiles and loads correctly,
> > rely on the user to manually select it?
> 
> When I changed the TXGBE config to:
> ...
> 	depends on SFP
> 	select PCS_XPCS
> ...
> the compilation gave an error:
> 
> drivers/net/phy/Kconfig:16:error: recursive dependency detected!
> drivers/net/phy/Kconfig:16:     symbol PHYLIB is selected by PHYLINK
> drivers/net/phy/Kconfig:6:      symbol PHYLINK is selected by PCS_XPCS
> drivers/net/pcs/Kconfig:8:      symbol PCS_XPCS is selected by TXGBE
> drivers/net/ethernet/wangxun/Kconfig:40:        symbol TXGBE depends on SFP
> drivers/net/phy/Kconfig:63:     symbol SFP depends on PHYLIB
> For a resolution refer to Documentation/kbuild/kconfig-language.rst
> subsection "Kconfig recursive dependency limitations"
> 
> Seems deleting "depends on SFP" is the correct way. But is this normal?
> How do we ensure the dependency between TXGBE and SFP?

Hi Russell,

Could you please give me some suggestions?

I checked "kconfig-language" doc, the practical solution is that swap all
"select FOO" to "depends on FOO" or swap all "depends on FOO" to
"select FOO". Config PCS_XPCS has to be selected in order to load modules
properly, so how should I fix the warning?