[alsa-devel] i8253 locking and PC speaker on non-{mips,x86}
No longer terribly relevant these days but ...
drivers/input/misc/pcspkr.c:
#if defined(CONFIG_MIPS) || defined(CONFIG_X86) /* Use the global PIT lock ! */ #include <asm/i8253.h> #else #include <asm/8253pit.h> static DEFINE_RAW_SPINLOCK(i8253_lock); #endif
sound/drivers/pcsp/pcsp.h:
#if defined(CONFIG_MIPS) || defined(CONFIG_X86) /* Use the global PIT lock ! */ #include <asm/i8253.h> #else #include <asm/8253pit.h> static DEFINE_RAW_SPINLOCK(i8253_lock);
$ git grep -F pcsp.h sound/drivers/pcsp sound/drivers/pcsp/pcsp.c:#include "pcsp.h" sound/drivers/pcsp/pcsp_input.c:#include "pcsp.h" sound/drivers/pcsp/pcsp_lib.c:#include "pcsp.h" sound/drivers/pcsp/pcsp_mixer.c:#include "pcsp.h" $ git grep -w i8253_lock sound/drivers/pcsp/ sound/drivers/pcsp/pcsp.h:static DEFINE_RAW_SPINLOCK(i8253_lock); sound/drivers/pcsp/pcsp_input.c: raw_spin_lock_irqsave(&i8253_lock, flags sound/drivers/pcsp/pcsp_input.c: raw_spin_unlock_irqrestore(&i8253_lock, sound/drivers/pcsp/pcsp_lib.c: raw_spin_lock_irqsave(&i8253_lock, flags sound/drivers/pcsp/pcsp_lib.c: raw_spin_unlock_irqrestore(&i8253_lock, sound/drivers/pcsp/pcsp_lib.c: raw_spin_lock(&i8253_lock); sound/drivers/pcsp/pcsp_lib.c: raw_spin_unlock(&i8253_lock); sound/drivers/pcsp/pcsp_lib.c: raw_spin_lock(&i8253_lock); sound/drivers/pcsp/pcsp_lib.c: raw_spin_unlock(&i8253_lock);
Locks are great, everybody should have their own lock!
$ find . -name 8253pit.h ./arch/powerpc/include/asm/8253pit.h ./arch/alpha/include/asm/8253pit.h $ cat arch/*/include/asm/8253pit.h /* * 8253/8254 Programmable Interval Timer */ /* * 8253/8254 Programmable Interval Timer */ $
Eh...
$ git grep -w PCSPKR_PLATFORM arch/mips/Kconfig: select PCSPKR_PLATFORM arch/mips/Kconfig: select PCSPKR_PLATFORM arch/mips/Kconfig: select PCSPKR_PLATFORM arch/powerpc/platforms/amigaone/Kconfig: select PCSPKR_PLATFORM drivers/input/misc/Kconfig: depends on PCSPKR_PLATFORM init/Kconfig:config PCSPKR_PLATFORM sound/drivers/Kconfig: depends on PCSPKR_PLATFORM && X86 && HIGH_RES_TIMERS
So works on MIPS and x86. Compiles on PowerPC but locking is wrong. On Alpha can't even be selected though it sees otherwise right except the locking and even worse for the rest.
Ralf
At Sat, 28 May 2011 12:21:20 +0100, Ralf Baechle wrote:
No longer terribly relevant these days but ...
drivers/input/misc/pcspkr.c:
#if defined(CONFIG_MIPS) || defined(CONFIG_X86) /* Use the global PIT lock ! */ #include <asm/i8253.h> #else #include <asm/8253pit.h> static DEFINE_RAW_SPINLOCK(i8253_lock); #endif
sound/drivers/pcsp/pcsp.h:
#if defined(CONFIG_MIPS) || defined(CONFIG_X86) /* Use the global PIT lock ! */ #include <asm/i8253.h> #else #include <asm/8253pit.h> static DEFINE_RAW_SPINLOCK(i8253_lock);
$ git grep -F pcsp.h sound/drivers/pcsp sound/drivers/pcsp/pcsp.c:#include "pcsp.h" sound/drivers/pcsp/pcsp_input.c:#include "pcsp.h" sound/drivers/pcsp/pcsp_lib.c:#include "pcsp.h" sound/drivers/pcsp/pcsp_mixer.c:#include "pcsp.h" $ git grep -w i8253_lock sound/drivers/pcsp/ sound/drivers/pcsp/pcsp.h:static DEFINE_RAW_SPINLOCK(i8253_lock); sound/drivers/pcsp/pcsp_input.c: raw_spin_lock_irqsave(&i8253_lock, flags sound/drivers/pcsp/pcsp_input.c: raw_spin_unlock_irqrestore(&i8253_lock, sound/drivers/pcsp/pcsp_lib.c: raw_spin_lock_irqsave(&i8253_lock, flags sound/drivers/pcsp/pcsp_lib.c: raw_spin_unlock_irqrestore(&i8253_lock, sound/drivers/pcsp/pcsp_lib.c: raw_spin_lock(&i8253_lock); sound/drivers/pcsp/pcsp_lib.c: raw_spin_unlock(&i8253_lock); sound/drivers/pcsp/pcsp_lib.c: raw_spin_lock(&i8253_lock); sound/drivers/pcsp/pcsp_lib.c: raw_spin_unlock(&i8253_lock);
Locks are great, everybody should have their own lock!
Yeah, if they were actually built. But snd-pcsp driver is built only for x86:
config SND_PCSP tristate "PC-Speaker support (READ HELP!)" depends on PCSPKR_PLATFORM && X86 && HIGH_RES_TIMERS depends on INPUT depends on EXPERIMENTAL
So, the current code in sound/drivers/pcsp/pcsp.h is harmless, but just confusing because of copy-and-paste from drivers/input/misc/pcspkr.c. The part for non-x86 should be removed or commented better.
thanks,
Takashi
participants (2)
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Ralf Baechle
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Takashi Iwai