On 2021/2/6 4:08, Bjorn Helgaas wrote:
On Fri, Feb 05, 2021 at 10:28:32AM -0800, Guenter Roeck wrote:
On Fri, Feb 05, 2021 at 05:44:13PM +0800, Yicong Yang wrote:
From: Junhao He hejunhao2@hisilicon.com
Use subdir-ccflags-* instead of ccflags-* to inherit the debug settings from Kconfig when traversing subdirectories.
Suggested-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Junhao He hejunhao2@hisilicon.com Signed-off-by: Yicong Yang yangyicong@hisilicon.com
What problem does this fix ? Maybe I am missing it, but I don't see DEBUG being used in a subdirectory of drivers/hwmon.
It's my fault for raising this question [1]. Yicong fixed a real problem in drivers/pci, where we are currently using
ccflags-$(CONFIG_PCI_DEBUG) := -DDEBUG
so CONFIG_PCI_DEBUG=y turns on debug in drivers/pci, but not in the subdirectories. That's surprising to users.
So my question was whether we should default to using subdir-ccflags for -DDEBUG in general, and only use ccflags when we have subdirectories that have their own debug options, e.g.,
drivers/i2c/Makefile:ccflags-$(CONFIG_I2C_DEBUG_CORE) := -DDEBUG drivers/i2c/algos/Makefile:ccflags-$(CONFIG_I2C_DEBUG_ALGO) := -DDEBUG drivers/i2c/busses/Makefile:ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG drivers/i2c/muxes/Makefile:ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
I mentioned drivers/hwmon along with a few others that have subdirectories, do not have per-subdirectory debug options, and use ccflags. I didn't try to determine whether those subdirectories currently use -DDEBUG.
In the case of drivers/hwmon, several drivers do use pr_debug(), and CONFIG_HWMON_DEBUG_CHIP=y turns those on. But if somebody were to add pr_debug() to drivers/hwmon/occ/common.c, for example, CONFIG_HWMON_DEBUG_CHIP=y would *not* turn it on. That sounds surprising to me, but if that's what you intend, that's totally fine.
i thought CONFIG_HWMON_DEBUG_CHIP=y means to enable debug including the subdirectories, so use subdir-ccflags-* will make sure the debug message on in the subdirectories, if there will be.
please let me know if i understand wrong.
Thanks, Yicong
[1] https://lore.kernel.org/r/20210204161048.GA68790@bjorn-Precision-5520
drivers/hwmon/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index 09a86c5..1c0c089 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -201,5 +201,5 @@ obj-$(CONFIG_SENSORS_XGENE) += xgene-hwmon.o obj-$(CONFIG_SENSORS_OCC) += occ/ obj-$(CONFIG_PMBUS) += pmbus/
-ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG +subdir-ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
-- 2.8.1
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