On Fri, 29 Feb 2008 12:01:26 +0100 (CET) Julia Lawall <julia@xxxxxxx> wrote: > On Thu, 28 Feb 2008, Andrew Morton wrote: > > > On Wed, 27 Feb 2008 19:29:15 +0100 Mark Pearson <devnull.port@xxxxxxxxxxxxxx> wrote: > > > > > Karol Kozimor wrote: > > > > On 26-02-2008, at 21:42, Julia Lawall wrote: > > > >> if (invert) /* invert target value */ > > > >> - led_out = !led_out & 0x1; > > > >> + led_out = !(led_out & 0x1); > > > >> > > > >> if (!write_acpi_int(hotk->handle, ledname, led_out, NULL)) > > > >> printk(KERN_WARNING "Asus ACPI: LED (%s) write failed\n", > > > > > > > > > > > > IIRC we're just supposed to flip the last bit here, so the original code > > > > is correct. > > > > Best regards, > > > > > > > > > > Seems an odd way of doing: > > > > > > led_out ^= 0x01; > > > > It does. > > > > > It this due to some optimisation? > > > > Surely not ;) > > > > That code has been there for many years. > > > > I changed the patch to this: > > > > --- a/drivers/acpi/asus_acpi.c~drivers-acpi-asus_acpic-correct-use-of-and > > +++ a/drivers/acpi/asus_acpi.c > > @@ -610,7 +610,7 @@ write_led(const char __user * buffer, un > > (led_out) ? (hotk->status | ledmask) : (hotk->status & ~ledmask); > > > > if (invert) /* invert target value */ > > - led_out = !led_out & 0x1; > > + led_out = !led_out; > > I don't think this is the same: > > !(0110 & 0x01) = !0 = 1 > !0110 = 0 > > led_out ^= 0x01; > > is also not the same: > > 0110 ^ 0x01 = 0111 > > Is it desired to keep the value and flip the last bit or just obtain the > opposite of the last bit? > led_out can only take the values 0 or 1 here. -- 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
