Re: [Qemu-devel] [PATCH 1/4] Confine use of global rtc_state to PC CMOS functions

[Blue Swirl <blauwirbel@gmail.com>]

On 5/4/09, Markus Armbruster <armbru@redhat.com> wrote:
> Blue Swirl <blauwirbel@gmail.com> writes:
>
>  > On 4/30/09, Markus Armbruster <armbru@redhat.com> wrote:
>  >> Pass the state as argument to cmos_init() and cmos_init_hd().
>  >>  cmos_init() still needs to save it in rtc_state for use by
>  >>  cmos_set_s3_resume().
>  >
>  > pc.c could pass acpi an opaque handle (former rtc_state) at init or
>  > acpi could export a function to set the handle, called by pc.c. Then
>  > cmos_set_s3_resume could take a state parameter.
>
>
> We'd just move a global variable from pc.c to acpi.c, wouldn't we?
>  Could you explain why that's a better place?

No, acpi would only have an opaque pointer to the variable stored in
PIIX4PMState, the "owner" would still be pc.c.

>  Passing rtc_state to piix4_pm_init() doesn't work well for pcdt.c,
>  because we'd have to pass it from RTC device to PIIX3 ACPI device
>  somehow, creating one of those ugly "non-tree" device dependencies,
>  i.e. one that doesn't follow device tree or interrupt tree edges.  Your
>  other idea (a function to set the handle) allows me to keep the two
>  devices decoupled, provided I can set the handle even before
>  piix4_pm_init().

Still one idea: a signal (qemu_irq) could be used to convey the s3
resume condition. That may be another tree.

Setting the handle before piix4_pm_init will fail if the handle is
going to be stored in PIIX4PMState, but the setup can be reversed:
piix4_pm_init can call a function to get the handle.