diff mbox series

[1/2] ALSA: emu10k1: make E-MU dock monitoring interrupt-driven

Message ID 20230710065956.1246364-1-oswald.buddenhagen@gmx.de
State Accepted
Commit fbb64eedf5a3a98071ee75808cfc1367d1e75783
Headers show
Series [1/2] ALSA: emu10k1: make E-MU dock monitoring interrupt-driven | expand

Commit Message

Oswald Buddenhagen July 10, 2023, 6:59 a.m. UTC 
... instead of using a one-second polling timer.

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
---
 include/sound/emu10k1.h          |  4 +--
 sound/pci/emu10k1/emu10k1.c      |  8 +----
 sound/pci/emu10k1/emu10k1_main.c | 51 ++++++++++++++++++--------------
 sound/pci/emu10k1/io.c           |  2 ++
 sound/pci/emu10k1/irq.c          |  7 +++++
 5 files changed, 40 insertions(+), 32 deletions(-)

Comments

Oswald Buddenhagen July 10, 2023, 5:34 p.m. UTC | #1 
On Mon, Jul 10, 2023 at 05:05:06PM +0200, Takashi Iwai wrote:
>On Mon, 10 Jul 2023 08:59:56 +0200,
>Oswald Buddenhagen wrote:
>> +	// We consider this a mixer setting, so use the mixer's lock
>> +	down_write(&emu->card->controls_rwsem);
>
>I really don't want to see the driver touching this lock.  It's
>basically an internal stuff of ALSA core code.  And, as already
>discussed, the controls_rwsem wasn't intended as a lock for the mixer
>content protection originally.  It took over the role partially, but
>the drivers shouldn't rely on it.
>
i know that this is technically true, but i think that from a pragmatic 
point of view it just makes no sense.

if we are pedantic about it, we need to revert my 06405d8ee8c (emu10k1: 
remove now superfluous mixer locking) and do the opposite change, to add 
the technically missing locks. that's several tens of irq-safe spinlock 
operations in this driver alone. which are hundreds of bytes spent 
entirely pointlessly, because we _know_ that the operation is already 
locked, because it must be.

so i think the most sensible approach is to just make it official, which 
is what my 37bb927d5bb (core: update comment on snd_card.controls_rwsem) 
actually works towards. at least i can't think of a reason not to do 
that, except for some puristic ideals.

if somebody actually finds a _good_ reason to change this and wants to 
embark on the mammoth task of proving that everything is still safe 
afterwards, they can just do so. adjusting this commit for the new 
reality wouldn't be hard or laborious.

> > +     snd_emu1010_update_clock(emu);
> > +     downgrade_write(&emu->card->controls_rwsem);
> > +     snd_ctl_build_ioff(&id, emu->ctl_clock_source, 0);
> > +     snd_ctl_notify(emu->card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
> > +     up_read(&emu->card->controls_rwsem);
> 
> Err, too ugly and unnecessary change.  snd_ctl_notify() doesn't take
> the rwsem, and it can be called at any place without fiddling the
> rwsem.  It's snd_ctl_notify_one() that needs the downgrade to read
> (and maybe we should rename the function to be clearer).
>
well, that lock is necessary exactly because we (ab-)use the rwsem as 
the general mixer lock, so we basically need to emulate the ioctl entry 
path, so a concurrent actual put ioctl doesn't blow up in our face. i 
actually agree that it's kinda ugly, but the argument remains the same - 
it just isn't worth doing it differently (we'd have to sprinkle around 
quite some reg_lock operations instead).

regards
Takashi Iwai July 11, 2023, 11:14 a.m. UTC | #2 
On Tue, 11 Jul 2023 12:11:30 +0200,
Oswald Buddenhagen wrote:
> 
> On Tue, Jul 11, 2023 at 07:28:22AM +0200, Takashi Iwai wrote:
> > Again, snd_ctl_notify() itself doesn't need the rwsem lock at all.
> > 
> ah, you mean i could fully release it before the notification.
> 
> > It's snd_ctl_notify_one() that needs a more careful call pattern.
> > 
> i suppose that's because the snd_ctl_layer callbacks might require it.
> i would recommend actually documenting that.

Yes, but this helper itself needs more change at first, I'm afraid.
The current implementation with the nested rwsem is fragile.  It's a
new stuff (or new restriction), and it's to be revisited.

> > And, that ugly implementation is a thing to be improved in future in
> > ALSA core side.
> > 
> it is? like, really?

Yes.  See my earlier RFC patch for reducing the nested rwlock, for
example.  Jaroslav didn't like the implementation, so it needs more
respin, though.

Another idea could to be make the controls_rwsem back to read-only for
both get and put, but introduce another lock just wrapping around
get/put call (but conditionally - there are drivers that don't need
it).  This will avoid the rwsem deadlock problem.


Takashi
diff mbox series

Patch

diff --git a/include/sound/emu10k1.h b/include/sound/emu10k1.h
index 386a5f3be3e0..43c097952c3c 100644
--- a/include/sound/emu10k1.h
+++ b/include/sound/emu10k1.h
@@ -1678,8 +1678,7 @@  struct snd_emu1010 {
 	unsigned int clock_fallback;
 	unsigned int optical_in; /* 0:SPDIF, 1:ADAT */
 	unsigned int optical_out; /* 0:SPDIF, 1:ADAT */
-	struct delayed_work firmware_work;
-	u32 last_reg;
+	struct work_struct firmware_work;
 };
 
 struct snd_emu10k1 {
@@ -1761,6 +1760,7 @@  struct snd_emu10k1 {
 	void (*capture_efx_interrupt)(struct snd_emu10k1 *emu, unsigned int status);
 	void (*spdif_interrupt)(struct snd_emu10k1 *emu, unsigned int status);
 	void (*dsp_interrupt)(struct snd_emu10k1 *emu);
+	void (*gpio_interrupt)(struct snd_emu10k1 *emu);
 	void (*p16v_interrupt)(struct snd_emu10k1 *emu);
 
 	struct snd_pcm_substream *pcm_capture_substream;
diff --git a/sound/pci/emu10k1/emu10k1.c b/sound/pci/emu10k1/emu10k1.c
index 23adace1b969..1a13c086e86c 100644
--- a/sound/pci/emu10k1/emu10k1.c
+++ b/sound/pci/emu10k1/emu10k1.c
@@ -176,9 +176,6 @@  static int snd_card_emu10k1_probe(struct pci_dev *pci,
 	if (err < 0)
 		return err;
 
-	if (emu->card_capabilities->emu_model)
-		schedule_delayed_work(&emu->emu1010.firmware_work, 0);
-
 	pci_set_drvdata(pci, card);
 	dev++;
 	return 0;
@@ -194,7 +191,7 @@  static int snd_emu10k1_suspend(struct device *dev)
 
 	emu->suspend = 1;
 
-	cancel_delayed_work_sync(&emu->emu1010.firmware_work);
+	cancel_work_sync(&emu->emu1010.firmware_work);
 
 	snd_ac97_suspend(emu->ac97);
 
@@ -224,9 +221,6 @@  static int snd_emu10k1_resume(struct device *dev)
 
 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
 
-	if (emu->card_capabilities->emu_model)
-		schedule_delayed_work(&emu->emu1010.firmware_work, 0);
-
 	return 0;
 }
 
diff --git a/sound/pci/emu10k1/emu10k1_main.c b/sound/pci/emu10k1/emu10k1_main.c
index 58ed72de6403..661164dbf547 100644
--- a/sound/pci/emu10k1/emu10k1_main.c
+++ b/sound/pci/emu10k1/emu10k1_main.c
@@ -391,7 +391,10 @@  static void snd_emu10k1_audio_enable(struct snd_emu10k1 *emu)
 	}
 #endif
 
-	snd_emu10k1_intr_enable(emu, INTE_PCIERRORENABLE);
+	if (emu->card_capabilities->emu_model)
+		snd_emu10k1_intr_enable(emu, INTE_PCIERRORENABLE | INTE_A_GPIOENABLE);
+	else
+		snd_emu10k1_intr_enable(emu, INTE_PCIERRORENABLE);
 }
 
 int snd_emu10k1_done(struct snd_emu10k1 *emu)
@@ -745,63 +748,61 @@  static void emu1010_firmware_work(struct work_struct *work)
 	int err;
 
 	emu = container_of(work, struct snd_emu10k1,
-			   emu1010.firmware_work.work);
+			   emu1010.firmware_work);
 	if (emu->card->shutdown)
 		return;
 #ifdef CONFIG_PM_SLEEP
 	if (emu->suspend)
 		return;
 #endif
-	snd_emu1010_fpga_read(emu, EMU_HANA_IRQ_STATUS, &tmp); /* IRQ Status */
 	snd_emu1010_fpga_read(emu, EMU_HANA_OPTION_CARDS, &reg); /* OPTIONS: Which cards are attached to the EMU */
 	if (reg & EMU_HANA_OPTION_DOCK_OFFLINE) {
 		/* Audio Dock attached */
 		/* Return to Audio Dock programming mode */
 		dev_info(emu->card->dev,
 			 "emu1010: Loading Audio Dock Firmware\n");
 		snd_emu1010_fpga_write(emu, EMU_HANA_FPGA_CONFIG,
 				       EMU_HANA_FPGA_CONFIG_AUDIODOCK);
 		err = snd_emu1010_load_firmware(emu, 1, &emu->dock_fw);
 		if (err < 0)
-			goto next;
-
+			return;
 		snd_emu1010_fpga_write(emu, EMU_HANA_FPGA_CONFIG, 0);
-		snd_emu1010_fpga_read(emu, EMU_HANA_IRQ_STATUS, &tmp);
-		dev_info(emu->card->dev,
-			 "emu1010: EMU_HANA+DOCK_IRQ_STATUS = 0x%x\n", tmp);
-		/* ID, should read & 0x7f = 0x55 when FPGA programmed. */
 		snd_emu1010_fpga_read(emu, EMU_HANA_ID, &tmp);
 		dev_info(emu->card->dev,
 			 "emu1010: EMU_HANA+DOCK_ID = 0x%x\n", tmp);
 		if ((tmp & 0x1f) != 0x15) {
 			/* FPGA failed to be programmed */
 			dev_info(emu->card->dev,
 				 "emu1010: Loading Audio Dock Firmware file failed, reg = 0x%x\n",
 				 tmp);
-			goto next;
+			return;
 		}
 		dev_info(emu->card->dev,
 			 "emu1010: Audio Dock Firmware loaded\n");
 		snd_emu1010_fpga_read(emu, EMU_DOCK_MAJOR_REV, &tmp);
 		snd_emu1010_fpga_read(emu, EMU_DOCK_MINOR_REV, &tmp2);
 		dev_info(emu->card->dev, "Audio Dock ver: %u.%u\n", tmp, tmp2);
 		/* Sync clocking between 1010 and Dock */
 		/* Allow DLL to settle */
 		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->emu1010.last_reg) {
+	}
+}
+
+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) {
+		schedule_work(&emu->emu1010.firmware_work);
 	}
-
- next:
-	emu->emu1010.last_reg = reg;
-	if (!emu->card->shutdown)
-		schedule_delayed_work(&emu->emu1010.firmware_work,
-				      msecs_to_jiffies(1000));
 }
 
 /*
@@ -870,6 +871,8 @@  static int snd_emu10k1_emu1010_init(struct snd_emu10k1 *emu)
 
 	snd_emu1010_fpga_read(emu, EMU_HANA_OPTION_CARDS, &reg);
 	dev_info(emu->card->dev, "emu1010: Card options = 0x%x\n", reg);
+	if (reg & EMU_HANA_OPTION_DOCK_OFFLINE)
+		schedule_work(&emu->emu1010.firmware_work);
 	if (emu->card_capabilities->no_adat) {
 		emu->emu1010.optical_in = 0; /* IN_SPDIF */
 		emu->emu1010.optical_out = 0; /* OUT_SPDIF */
@@ -895,10 +898,12 @@  static int snd_emu10k1_emu1010_init(struct snd_emu10k1 *emu)
 	/* MIDI routing */
 	snd_emu1010_fpga_write(emu, EMU_HANA_MIDI_IN, EMU_HANA_MIDI_INA_FROM_HAMOA | EMU_HANA_MIDI_INB_FROM_DOCK2);
 	snd_emu1010_fpga_write(emu, EMU_HANA_MIDI_OUT, EMU_HANA_MIDI_OUT_DOCK2 | EMU_HANA_MIDI_OUT_SYNC2);
-	/* IRQ Enable: All on */
-	/* snd_emu1010_fpga_write(emu, EMU_HANA_IRQ_ENABLE, 0x0f); */
-	/* IRQ Enable: All off */
-	snd_emu1010_fpga_write(emu, EMU_HANA_IRQ_ENABLE, 0x00);
+
+	emu->gpio_interrupt = emu1010_interrupt;
+	// Note: The Audigy INTE is set later
+	snd_emu1010_fpga_write(emu, EMU_HANA_IRQ_ENABLE,
+			       EMU_HANA_IRQ_DOCK | EMU_HANA_IRQ_DOCK_LOST);
+	snd_emu1010_fpga_read(emu, EMU_HANA_IRQ_STATUS, &reg);  // Clear pending IRQs
 
 	emu->emu1010.clock_source = 1;  /* 48000 */
 	emu->emu1010.clock_fallback = 1;  /* 48000 */
@@ -938,7 +943,7 @@  static void snd_emu10k1_free(struct snd_card *card)
 		/* Disable 48Volt power to Audio Dock */
 		snd_emu1010_fpga_write(emu, EMU_HANA_DOCK_PWR, 0);
 	}
-	cancel_delayed_work_sync(&emu->emu1010.firmware_work);
+	cancel_work_sync(&emu->emu1010.firmware_work);
 	release_firmware(emu->firmware);
 	release_firmware(emu->dock_fw);
 	snd_util_memhdr_free(emu->memhdr);
@@ -1517,7 +1522,7 @@  int snd_emu10k1_create(struct snd_card *card,
 	emu->irq = -1;
 	emu->synth = NULL;
 	emu->get_synth_voice = NULL;
-	INIT_DELAYED_WORK(&emu->emu1010.firmware_work, emu1010_firmware_work);
+	INIT_WORK(&emu->emu1010.firmware_work, emu1010_firmware_work);
 	/* read revision & serial */
 	emu->revision = pci->revision;
 	pci_read_config_dword(pci, PCI_SUBSYSTEM_VENDOR_ID, &emu->serial);
diff --git a/sound/pci/emu10k1/io.c b/sound/pci/emu10k1/io.c
index a0d66ce3ee83..c695cb863e5e 100644
--- a/sound/pci/emu10k1/io.c
+++ b/sound/pci/emu10k1/io.c
@@ -302,6 +302,8 @@  static void snd_emu1010_fpga_read_locked(struct snd_emu10k1 *emu, u32 reg, u32 *
 {
 	// The higest input pin is used as the designated interrupt trigger,
 	// so it needs to be masked out.
+	// But note that any other input pin change will also cause an IRQ,
+	// so using this function often causes an IRQ as a side effect.
 	u32 mask = emu->card_capabilities->ca0108_chip ? 0x1f : 0x7f;
 	if (snd_BUG_ON(reg > 0x3f))
 		return;
diff --git a/sound/pci/emu10k1/irq.c b/sound/pci/emu10k1/irq.c
index a813ef8c2f8d..8573248dd799 100644
--- a/sound/pci/emu10k1/irq.c
+++ b/sound/pci/emu10k1/irq.c
@@ -149,6 +149,13 @@  irqreturn_t snd_emu10k1_interrupt(int irq, void *dev_id)
 				outl(0, emu->port + INTE2);
 			status &= ~IPR_P16V;
 		}
+		if (status & IPR_A_GPIO) {
+			if (emu->gpio_interrupt)
+				emu->gpio_interrupt(emu);
+			else
+				snd_emu10k1_intr_disable(emu, INTE_A_GPIOENABLE);
+			status &= ~IPR_A_GPIO;
+		}
 
 		if (status) {
 			dev_err(emu->card->dev,