Date: Tue, 16 Nov 2004 00:21:53 -0800 From: Nate Lawson <nate@root.org> To: "M. Warner Losh" <imp@bsdimp.com> Cc: acpi@FreeBSD.org Subject: Re: Minor improvement to acpiconf Message-ID: <4199B8A1.6080205@root.org> In-Reply-To: <20041116.001446.66168349.imp@bsdimp.com> References: <20041115.231816.133541642.imp@bsdimp.com> <4199A260.3020001@root.org> <20041116.001446.66168349.imp@bsdimp.com>
next in thread | previous in thread | raw e-mail | index | archive | help
M. Warner Losh wrote:
> In message: <4199A260.3020001@root.org>
> Nate Lawson <nate@root.org> writes:
>
> : > acpifd = open(ACPIDEV, O_RDWR);
> : > if (acpifd == -1){
> : > @@ -117,6 +117,17 @@
> : > printf("Type:\t\t\t%s\n", battio.bif.type);
> : > printf("OEM info:\t\t%s\n", battio.bif.oeminfo);
> : >
> : > + if (ioctl(acpifd, ACPIIO_CMBAT_GET_BST, &battio) == -1)
> : > + err(EX_IOERR, "get battery info (%d) failed", num);
> : > +
> : > + if (battio.bst.state != ACPI_BATT_STAT_NOT_PRESENT) {
> :
> : Prefer positive logic.
>
> Most common path first is generally the logic I prefer...
I thought there was a PRESENT define but apparently not.
> : > + printf("State:\t\t\tPresent\n");
> : > + printf("Rate:\t\t\t%d mWh\n", battio.bst.rate);
> : > + printf("Cap:\t\t\t%d mWh\n", battio.bst.cap);
> : > + printf("Volt:\t\t\t%d mV\n", battio.bst.volt);
> :
> : I agree with these except for a slight misgiving about "cap". That
> : information is already exported via sysctl and if we have to export the
> : same thing different ways, I think the interface is not optimal.
>
> Capacity isnt' exported via a sysctl. 'life' is, but it doesn't
> export anything more than a percentage.
Life is derived from cap, but like I said above, I'm ok with it.
> : In general, I'd like to move away from acpi-specific ioctls. There
> : should be just one way of getting the battery info and it shouldn't
> : refer to the underlying method names (_BST and _BIF) like the current
> : ones do. Mike made a good case for eliminating the dev_t entirely since
> : there is never any IO for acpi, it's all control traffic. Sysctl seems
> : more appropriate for that than creating a device that will never see a
> : read, write, or other access other than ioctl(). But this is a
> : complaint about the current design and the half-ioctl, half-sysctl
> : implementation.
>
> I'm not entirely sure I agree with a device needing read/write methods
> to be legit. Especially after I saw sysctl abused for the devinfo
> interface, which likely should have been read instead :-)...
Looking in /dev, nearly all devices support IO. Only the .ctl or
.init/.lock devices are questionable. I think it makes sense for this
to be a criterion for using a dev_t.
-Nate
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4199B8A1.6080205>