Messages in this thread | | | Date | Mon, 21 Mar 2022 14:51:36 +0000 | From | David Cohen <> | Subject | Re: [PATCH v2] PM: fix dynamic debug within pm_pr_debug() |
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On Mon, Mar 21, 2022 at 03:20:20PM +0100, Rafael J. Wysocki wrote: > 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?
Let me be a bit more detailed:
Before "8d8b2441db96 PM / sleep: Do not print debug messages by default": - pr_debug() was used - The kernel pm files had dynamic debug support - All the instances using pr_debug() are visible on /sys/kernel/debug/dynamic_debug/control - pm_debug_messages_on flag was not supported
After "8d8b2441db96 PM / sleep: Do not print debug messages by default": - pr_debug() was replaced with pm_pr_dbg() - The kernel pm files where pm_pr_dbg() replaced pr_debug() *lost* dynamic debug support and they are no longer visible on /sys/kernel/debug/dynamic_debug/control - pm_debug_messages_on flag was introduced
What my patch is doing: - Reintroducing dynamic debug support to the same files who lost it after the patch mentioned above - The instances using pr_pm_dbg() (which originally came from pr_debug()) are reintroduced to /sys/kernel/debug/dynamic_debug/control - pm_debug_messages_on flag is unaltered
Regards, David
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