On 2014/8/2 0:42, Kasagar, Srinidhi wrote: > On Fri, Aug 01, 2014 at 11:27:15AM +0300, Dan Carpenter wrote: >> I don't know if we really need 64 bits here but these variables are >> declared as u64 and it can't hurt to cast this so we prevent any shift >> wrapping. > > Hmm..not sure the usage of u64 for these registers. AFAIK these registers > are 32-bit wide.. I didn't declare the registers, I declared the variables in microsecond. > > Aubrey, any reason declaring them as u64? These registers are the time spent in units of 32us. So yes, we need 64bits here for the conversion. > > Srinidhi > >> >> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> The patch looks good to me. Acked-by: Aubrey Li <aubrey.li@xxxxxxxxxxxxxxx> >> >> diff --git a/arch/x86/kernel/pmc_atom.c b/arch/x86/kernel/pmc_atom.c >> index 0d92ef6..0c424a6 100644 >> --- a/arch/x86/kernel/pmc_atom.c >> +++ b/arch/x86/kernel/pmc_atom.c >> @@ -174,11 +174,11 @@ static int pmc_sleep_tmr_show(struct seq_file *s, void *unused) >> struct pmc_dev *pmc = s->private; >> u64 s0ir_tmr, s0i1_tmr, s0i2_tmr, s0i3_tmr, s0_tmr; >> >> - s0ir_tmr = pmc_reg_read(pmc, PMC_S0IR_TMR) << PMC_TMR_SHIFT; >> - s0i1_tmr = pmc_reg_read(pmc, PMC_S0I1_TMR) << PMC_TMR_SHIFT; >> - s0i2_tmr = pmc_reg_read(pmc, PMC_S0I2_TMR) << PMC_TMR_SHIFT; >> - s0i3_tmr = pmc_reg_read(pmc, PMC_S0I3_TMR) << PMC_TMR_SHIFT; >> - s0_tmr = pmc_reg_read(pmc, PMC_S0_TMR) << PMC_TMR_SHIFT; >> + s0ir_tmr = (u64)pmc_reg_read(pmc, PMC_S0IR_TMR) << PMC_TMR_SHIFT; >> + s0i1_tmr = (u64)pmc_reg_read(pmc, PMC_S0I1_TMR) << PMC_TMR_SHIFT; >> + s0i2_tmr = (u64)pmc_reg_read(pmc, PMC_S0I2_TMR) << PMC_TMR_SHIFT; >> + s0i3_tmr = (u64)pmc_reg_read(pmc, PMC_S0I3_TMR) << PMC_TMR_SHIFT; >> + s0_tmr = (u64)pmc_reg_read(pmc, PMC_S0_TMR) << PMC_TMR_SHIFT; >> >> seq_printf(s, "S0IR Residency:\t%lldus\n", s0ir_tmr); >> seq_printf(s, "S0I1 Residency:\t%lldus\n", s0i1_tmr); > -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
