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ALSA: emu10k1: make E-MU FPGA writes potentially more reliable

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[ Upstream commit 15c7e87aa8 ]

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>
This commit is contained in:
Oswald Buddenhagen 2024-04-28 11:37:16 +02:00 committed by Greg Kroah-Hartman
parent af8dc212f7
commit 107c893e0a
1 changed files with 1 additions and 0 deletions
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sound/pci/emu10k1/io.c
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@ -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)