Messages in this thread Patch in this message | | | Date | Sat, 24 Sep 2022 16:06:15 +0200 | From | Dominik Brodowski <> | Subject | Re: [PATCH] pcmcia: Removed unused variable control. |
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Am Fri, Sep 23, 2022 at 08:58:47AM +0200 schrieb Arnd Bergmann: > On Thu, Sep 22, 2022, at 4:39 PM, Dominik Brodowski wrote: > > Am Mon, Jul 25, 2022 at 06:59:55AM +0530 schrieb Souptick Joarder: > >> From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com> > >> > >> Kernel test robot throws below warning -> > >> drivers/pcmcia/omap_cf.c:127:7: warning: variable 'control' > >> set but not used [-Wunused-but-set-variable] > >> > >> Removed unused variable control. > > > > From a code-generation standpoint, this is obiously correct, and probably > > the compiler removes that omap_readw() already. > > omap_readw() is an 'extern' function, so it does not get removed. > > Even if it was inline, it's still "and volatile" read that gets > left in because it may (and probably does) have side-effects. > > > But, to be honest, I'm not > > perfectly sure on what the device expects -- and whether it's required to > > write back the control register (or parts of it). Does anyone still have the > > hardware (or specs)? If not, I'm tempted to apply this patch on the basis > > that the compiler might remove that omap_readw() anyway. > > I think assigning to an unused variable was at some point needed to > avoid a compiler warning because otherwise omap_readw() was just a > pointer dereference. The safe way to transform the code should be to > drop the variable but leave the function call. > > Note that the driver is only used on the 'osk' reference board, > not on any devices that were in mass-production.
Thanks for the evaluation, Arnd! So here's what I intend to push upstream:
From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
Kernel test robot throws below warning -> drivers/pcmcia/omap_cf.c:127:7: warning: variable 'control' set but not used [-Wunused-but-set-variable]
Removed unused variable control.
Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com> [linux@dominikbrodowski.net: retain omap_readw() call, as it might be required] Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
diff --git a/drivers/pcmcia/omap_cf.c b/drivers/pcmcia/omap_cf.c index 1972a8f6fa8e..d3f827d4224a 100644 --- a/drivers/pcmcia/omap_cf.c +++ b/drivers/pcmcia/omap_cf.c @@ -124,8 +124,6 @@ static int omap_cf_get_status(struct pcmcia_socket *s, u_int *sp) static int omap_cf_set_socket(struct pcmcia_socket *sock, struct socket_state_t *s) { - u16 control; - /* REVISIT some non-OSK boards may support power switching */ switch (s->Vcc) { case 0: @@ -135,7 +133,7 @@ omap_cf_set_socket(struct pcmcia_socket *sock, struct socket_state_t *s) return -EINVAL; } - control = omap_readw(CF_CONTROL); + omap_readw(CF_CONTROL); if (s->flags & SS_RESET) omap_writew(CF_CONTROL_RESET, CF_CONTROL); else
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