ALSA: emu10k1: fix E-MU dock initialization

[ 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>

diff --git a/sound/pci/emu10k1/emu10k1_main.c b/sound/pci/emu10k1/emu10k1_main.c
index 86eaf5963502c46bad0c9ac982d14634f4e44b42..ade90c7ecd922bcebe2a6edd0abe5e6f2b854e8b 100644 (file)
--- 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,