Hi Chris,
Thanks for the quick reply! I understand the idea better now. Just a
minor follow-up question..
The power_restore function for sdio also uses this flag, which is a
little bit strange I think. Especially since the mmc_power_off|up is
always called no matter of the value of this flag.
Br
Ulf Hansson
Chris Ball wrote:
Hi,
On Tue, Nov 22 2011, Ulf Hansson wrote:
Hi,
In mmc_resume_host we clear the MMC_PM_KEEP_POWER flag from the
pm_flags bitfield. This is done by a patch from Eliad Peller a while
ago, "mmc: clear MMC_PM_KEEP_POWER flag on resume"
I would like to understand if there are any reason to why we want to
clear this flag after we done a resume. I think it will add complexity
to an sdio function driver since it must update this flag for after
each suspend/resume sequence. Should it not just be enough to do this
during the initialization of the sdio func driver.
The sdio function driver should just call sdio_set_host_pm_flags() in
its suspend function, if it wants to stay awake at the next suspend.
It's just one line of code, so I don't think it's overly complex.
We clear the flag because that's how the API is defined --
sdio_set_host_pm_flags() says "This must be called, if needed, each
time the suspend method of the function driver is called".
There's a separate question of "Why is the API this way, and should
we change it?". I think the API ended up this way because it was
created for a wifi device where a suspend would usually happen while
you're unassociated, so you don't need to preserve power (because
nothing interesting can happen to wake you up), but will sometimes
happen while you're associated, in which case you do. It sounds like
you're considering a device that *always* wants to stay awake, which
is different to the rest of the users of this API.
But it's just the difference between (your proposal) having
sdio_set_host_pm_flags() be called during init, and (the API) having
sdio_set_host_pm_flags() be called during suspend. It's the same
line of code either way, so I don't see why it's annoying this way.
Thanks,
- Chris.
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