Messages in this thread | | | Date | Fri, 3 Jan 2020 18:53:18 +0100 | From | Andrew Lunn <> | Subject | Re: [PATCH] net: 3com: 3c59x: remove set but not used variable 'mii_reg1' |
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On Fri, Jan 03, 2020 at 06:46:23AM -0800, Matthew Wilcox wrote: > On Fri, Jan 03, 2020 at 08:19:07PM +0800, yu kuai wrote: > > Fixes gcc '-Wunused-but-set-variable' warning: > > > > drivers/net/ethernet/3com/3c59x.c: In function ‘vortex_up’: > > drivers/net/ethernet/3com/3c59x.c:1551:9: warning: variable > > ‘mii_reg1’ set but not used [-Wunused-but-set-variable] > > > > It is never used, and so can be removed. > ... > > if (dev->if_port == XCVR_MII || dev->if_port == XCVR_NWAY) { > > - mii_reg1 = mdio_read(dev, vp->phys[0], MII_BMSR); > > mii_reg5 = mdio_read(dev, vp->phys[0], MII_LPA); > > I know nothing about the MII interface, but in general this is not > a safe thing to do.
Hi Matthew
I fully agree about the general case. However, reading the MII_BMSR should not have any side affects. It would be an odd Ethernet PHY if it did.
But I am curious why this read is here. There is a slim change the MDIO bus is broken, and this is a workaround. So it would be good if somebody dug into the history and found out when this read was added and if there are any comments about why it is there. Or if the usage of mii_reg1 as been removed at some point, and the read was not cleaned up.
Andrew
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