Messages in this thread | | | Subject | Re: [PATCH 0/4]Bind physical devices with ACPI devices - take 2 | From | Li Shaohua <> | Date | Thu, 06 Jan 2005 15:50:34 +0800 |
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On Thu, 2005-01-06 at 12:00, Len Brown wrote: > I think we'll save some significant power when ACPI D-states > are invoked for the devices that supply them. While many > PCI devices support PCI power management and thus don't need/use > ACPI D-states, I think it will be even more important to add > this functionality to the legacy devices which never have > PCI power management and thus always depend on ACPI for D-states. It's easy to link the PNP devices with the ACPI devices with the ACPIPNP driver. But the PNP driver core hasn't similar routines as 'pnp_set_power_state'. Unclear if the PNP drivers support suspend/resume.
> It looks like some device drivers scribble on dev->platform_data; > and we need to fix those drivers before deploying this patch. > Alternatively, we could add a new field to struct device, > but then we'd probably never get rid of it... Yep, this is a big problem. According to the comments in the source file, it's designed for firmware such as ACPI, but some drivers misused it. A search shows there are many such drivers. Fixing the drivers is a pain for me.
> I'm a little unformforable with platform_notify > and platform_notify_remove available as globals. > We should probably BUG_ON if we > find them set before ACPI writes on them. I will fix it.
> We'll need to update this patch to handle erroneous > but real platforms that don't have _BBN > by using _CRS to get PCI bus number. That's ok.
> Unclear to me if/how this association of ACPI capability > should be reflected in the sysfs device tree. Possibly both the physical devices and ACPI devices have a link in sysfs to pointer partners.
Thanks, Shaohua
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