6.8-stable review patch. If anyone has any objections, please let me know.
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From: Oswald Buddenhagen oswald.buddenhagen@gmx.de
[ Upstream commit 15c7e87aa88f0ab2d51c2e2123b127a6d693ca21 ]
We did not delay after the second strobe signal, so another immediately following access could potentially corrupt the written value.
This is a purely speculative fix with no supporting evidence, but after taking out the spinlocks around the writes, it seems plausible that a modern processor could be actually too fast. Also, it's just cleaner to be consistent.
Signed-off-by: Oswald Buddenhagen oswald.buddenhagen@gmx.de Signed-off-by: Takashi Iwai tiwai@suse.de Message-ID: 20240428093716.3198666-7-oswald.buddenhagen@gmx.de Signed-off-by: Sasha Levin sashal@kernel.org --- sound/pci/emu10k1/io.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/pci/emu10k1/io.c b/sound/pci/emu10k1/io.c index 74df2330015f6..5cb8acf5b158c 100644 --- a/sound/pci/emu10k1/io.c +++ b/sound/pci/emu10k1/io.c @@ -285,6 +285,7 @@ static void snd_emu1010_fpga_write_locked(struct snd_emu10k1 *emu, u32 reg, u32 outw(value, emu->port + A_GPIO); udelay(10); outw(value | 0x80 , emu->port + A_GPIO); /* High bit clocks the value into the fpga. */ + udelay(10); }
void snd_emu1010_fpga_write(struct snd_emu10k1 *emu, u32 reg, u32 value)