Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Mon, 21 Mar 2022 15:20:20 +0100 | Subject | Re: [PATCH v2] PM: fix dynamic debug within pm_pr_debug() |
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On Sat, Mar 19, 2022 at 2:54 AM David Cohen <dacohen@pm.me> wrote: > > On Thu, Mar 17, 2022 at 02:45:11PM +0100, Rafael J. Wysocki wrote: > > On Sat, Mar 12, 2022 at 5:37 AM David Cohen <dacohen@pm.me> wrote: > > > > > > Currently, pm_pr_debug() and pm_deferred_pr_debug() use __pm_pr_debug() > > > to filter pm debug messages based on pm_debug_messages_on flag. > > > According to __pm_pr_debug() implementation, pm_deferred_pr_debug() > > > indirectly calls printk_deferred() within __pm_pr_debug() which doesn't > > > support dynamic debug, but pm_pr_debug() indirectly calls pr_debug() > > > > I'm not sure what you mean by pm_pr_debug(). There's no such thing in > > the kernel tree. > > > > Assuming that it means pm_pr_dbg(), it doesn't call pr_debug(): > > Yeah, I apologize for the typo. I meant pm_pr_dbg(). I can fix that if > you're ok with the patch as per comments below. > > > > > #define pm_pr_dbg(fmt, ...) __pm_pr_dbg(false, fmt, ##__VA_ARGS__) > > > > and > > > > void __pm_pr_dbg(bool defer, const char *fmt, ...) > > { > > ... > > if (defer) > > printk_deferred(KERN_DEBUG "PM: %pV", &vaf); > > else > > printk(KERN_DEBUG "PM: %pV", &vaf); > > > > And as I said printk(KERN_DEBUG ...) is not equivalent to > > pr_debug(...), because it is not dynamic printk(). > > The problem is not about __pm_pr_dbg() calling printk(). The problem is > the pm files that used to call pr_debug() were modified to call > pm_pr_dbg() in order to be behing the pm_debug_messages_on flag, as per > this commit: > 8d8b2441db96 PM / sleep: Do not print debug messages by default
So what's the problem with setting pm_debug_messages_on in addition to enabling dynamic debug for a given file?
> That's the moment dynamic debug was no longer available for kernel pm files. > > > > > pm_pr_dbg() is not dynamic printk() on purpose, so they both can be > > controlled independently. > > The current solution is all or nothing (using pm_debug_messages_on). The > patch I'm sending is making dynamic debug available on the kernel pm > files, while still allowing the pm_debug_messages_on flag to work > independently.
If you need a combination of pm_debug_messages_on and the pr_debug() type of dynamic debug, I would suggest adding a new macro, say pm_pr_dbg_dyn() or similar, for this purpose and use it as needed instead of attempting to modify the existing behavior everywhere.
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