[PATCH 6.8 056/336] ALSA: emu10k1: fix E-MU dock initialization

Greg Kroah-Hartman
2024-05-14T10:26:43Z

From: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

[ Upstream commit e8289fd3fa65d60cf04dab6f7845eda352c04ea6 ]

A side effect of making the dock monitoring interrupt-driven was that
we'd be very quick to program a freshly connected dock. However, for
unclear reasons, the dock does not work when we do that - despite the
FPGA netlist upload going just fine. We work around this by adding a
delay before programming the dock; for safety, the value is several
times as much as was determined empirically.

Note that a badly timed dock hot-plug would have triggered the problem
even before the referenced commit - but now it would happen 100% instead
of about 3% of the time, thus making it impossible to work around by
re-plugging.

Fixes: fbb64eedf5a3 ("ALSA: emu10k1: make E-MU dock monitoring interrupt-driven")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218584
Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Message-ID: <20240428093716.3198666-6-oswald.buddenhagen@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/pci/emu10k1/emu10k1_main.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/sound/pci/emu10k1/emu10k1_main.c b/sound/pci/emu10k1/emu10k1_main.c
index 86eaf5963502c..ade90c7ecd922 100644
--- a/sound/pci/emu10k1/emu10k1_main.c
+++ b/sound/pci/emu10k1/emu10k1_main.c
@@ -737,6 +737,12 @@ static void snd_emu1010_load_dock_firmware(struct snd_emu10k1 *emu)
u32 tmp, tmp2;
int err;

+ // The docking events clearly arrive prematurely - while the
+ // Dock's FPGA seems to be successfully programmed, the Dock
+ // fails to initialize subsequently if we don't give it some
+ // time to "warm up" here.
+ msleep(200);
+
dev_info(emu->card->dev, "emu1010: Loading Audio Dock Firmware\n");
/* Return to Audio Dock programming mode */
snd_emu1010_fpga_write(emu, EMU_HANA_FPGA_CONFIG,
--
2.43.0