ALSA: emu10k1: fix E-MU card dock presence monitoring

While there are two separate IRQ status bits for dock attach and detach,
the hardware appears to mix them up more or less randomly, making them
useless for tracking what actually happened. It is much safer to check
the dock status separately and proceed based on that, as the old polling
code did.

Note that the code assumes that only the dock can be hot-plugged - if
other option card bits changed, the logic would break.

Fixes: fbb64ee ("ALSA: emu10k1: make E-MU dock monitoring interrupt-driven")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218584
Signed-off-by: Oswald Buddenhagen <[email protected]>
Signed-off-by: Takashi Iwai <[email protected]>
Message-ID: <[email protected]>

sound/pci/emu10k1/emu10k1_main.c

@@ -778,6 +778,11 @@ static void emu1010_firmware_work(struct work_struct *work)
 		msleep(10);
 		/* Unmute all. Default is muted after a firmware load */
 		snd_emu1010_fpga_write(emu, EMU_HANA_UNMUTE, EMU_UNMUTE);
+	} else if (!(reg & EMU_HANA_OPTION_DOCK_ONLINE)) {
+		/* Audio Dock removed */
+		dev_info(emu->card->dev, "emu1010: Audio Dock detached\n");
+		/* The hardware auto-mutes all, so we unmute again */
+		snd_emu1010_fpga_write(emu, EMU_HANA_UNMUTE, EMU_UNMUTE);
 	}
 }
 
@@ -810,14 +815,12 @@ static void emu1010_interrupt(struct snd_emu10k1 *emu)
 	u32 sts;
 
 	snd_emu1010_fpga_read(emu, EMU_HANA_IRQ_STATUS, &sts);
-	if (sts & EMU_HANA_IRQ_DOCK_LOST) {
-		/* Audio Dock removed */
-		dev_info(emu->card->dev, "emu1010: Audio Dock detached\n");
-		/* The hardware auto-mutes all, so we unmute again */
-		snd_emu1010_fpga_write(emu, EMU_HANA_UNMUTE, EMU_UNMUTE);
-	} else if (sts & EMU_HANA_IRQ_DOCK) {
+
+	// The distinction of the IRQ status bits is unreliable,
+	// so we dispatch later based on option card status.
+	if (sts & (EMU_HANA_IRQ_DOCK | EMU_HANA_IRQ_DOCK_LOST))
 		schedule_work(&emu->emu1010.firmware_work);
-	}
+
 	if (sts & EMU_HANA_IRQ_WCLK_CHANGED)
 		schedule_work(&emu->emu1010.clock_work);
 }