[PATCH] ALSA: emu10k1: fix 64-bit integer division

[PATCH] ALSA: emu10k1: fix 64-bit integer division

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

Division of 64-bit values causes a link failure on 32-bit targets, depending
on compiler version and target architecture:

ERROR: modpost: "__divdi3" [sound/pci/emu10k1/snd-emu10k1.ko] undefined!
ERROR: modpost: "__udivdi3" [sound/pci/emu10k1/snd-emu10k1.ko] undefined!

Replace these with the safe div_u64() helpers.

Fixes: bb5ceb43b7bf ("ALSA: emu10k1: fix non-zero mixer control defaults in highres mode")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 sound/pci/emu10k1/emufx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/pci/emu10k1/emufx.c b/sound/pci/emu10k1/emufx.c
index f64b2b4eb348..7c28789720d1 100644
--- a/sound/pci/emu10k1/emufx.c
+++ b/sound/pci/emu10k1/emufx.c
@@ -1156,7 +1156,7 @@ snd_emu10k1_init_mono_control(struct snd_emu10k1_fx8010_control_gpr *ctl,
 		ctl->max = 0x7fffffff;
 		ctl->tlv = snd_emu10k1_db_linear;
 		ctl->translation = EMU10K1_GPR_TRANSLATION_NEGATE;
-		defval = defval * 0x80000000LL / 100 - 1;
+		defval = div_u64(defval * 0x80000000LL, 100) - 1;
 	} else {
 		ctl->min = 0;
 		ctl->max = 100;
@@ -1178,7 +1178,7 @@ snd_emu10k1_init_stereo_control(struct snd_emu10k1_fx8010_control_gpr *ctl,
 		ctl->max = 0x7fffffff;
 		ctl->tlv = snd_emu10k1_db_linear;
 		ctl->translation = EMU10K1_GPR_TRANSLATION_NEGATE;
-		defval = defval * 0x80000000LL / 100 - 1;
+		defval = div_u64(defval * 0x80000000LL, 100) - 1;
 	} else {
 		ctl->min = 0;
 		ctl->max = 100;
-- 
2.39.2

Re: [PATCH] ALSA: emu10k1: fix 64-bit integer division

[Takashi Iwai]

On Wed, 17 May 2023 22:19:17 +0200,
Arnd Bergmann wrote:
> 
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Division of 64-bit values causes a link failure on 32-bit targets, depending
> on compiler version and target architecture:
> 
> ERROR: modpost: "__divdi3" [sound/pci/emu10k1/snd-emu10k1.ko] undefined!
> ERROR: modpost: "__udivdi3" [sound/pci/emu10k1/snd-emu10k1.ko] undefined!
> 
> Replace these with the safe div_u64() helpers.
> 
> Fixes: bb5ceb43b7bf ("ALSA: emu10k1: fix non-zero mixer control defaults in highres mode")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Another fix patch was already submitted and merged:
 https://lore.kernel.org/r/20230517164800.3650699-1-oswald.buddenhagen@gmx.de

Let me know if you still hit the issue with that patch.


thanks,

Takashi