[PATCH](s): Use spinlocks instead of STI/CLI in SoundBlaster

Chris Rankin (rankinc@zip.com.au)
Fri, 26 Jan 2001 17:42:27 +1100 (EST)

Hi,

I hear on the grapevine that 2.4 kernel modules should use spinlocks
in preference to cli() and sti(). Well I'm not sure how big a win it
is, particularly on a UP machine, but here's a patch for the
SoundBlaster. I've added a spinlock_t to the "struct b_devc" so that
multiple SoundBlasters each get their own lock. After all, each SB has
its own IRQ and IO, correct?

There also seems to be something here called a Jazz16. This has a
global lock because it looks like there can only be one of them.

--- linux-2.4.0/drivers/sound/sb.h.orig Fri Jan 26 13:57:40 2001
+++ linux-2.4.0/drivers/sound/sb.h Fri Jan 26 13:58:42 2001
@@ -137,6 +137,8 @@
void (*midi_input_intr) (int dev, unsigned char data);
void *midi_irq_cookie; /* IRQ cookie for the midi */

+ spinlock_t lock;
+
struct sb_module_options sbmo; /* Module options */

} sb_devc;
--- linux-2.4.0/drivers/sound/sb_audio.c.orig Fri Jan 26 13:54:56 2001
+++ linux-2.4.0/drivers/sound/sb_audio.c Fri Jan 26 15:16:59 2001
@@ -19,8 +19,11 @@
* Daniel J. Rodriksson: Changes to make sb16 work full duplex.
* Maybe other 16 bit cards in this code could behave
* the same.
+ * Chris Rankin: Use spinlocks instead of CLI/STI
*/

+#include <linux/spinlock.h>
+
#include "sound_config.h"

#include "sb_mixer.h"
@@ -43,23 +46,22 @@
if (mode == OPEN_READ)
return -EPERM;
}
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (devc->opened)
{
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
return -EBUSY;
}
if (devc->dma16 != -1 && devc->dma16 != devc->dma8 && !devc->duplex)
{
if (sound_open_dma(devc->dma16, "Sound Blaster 16 bit"))
{
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
return -EBUSY;
}
}
devc->opened = mode;
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

devc->irq_mode = IMODE_NONE;
devc->irq_mode_16 = IMODE_NONE;
@@ -182,8 +184,7 @@

devc->irq_mode = IMODE_OUTPUT;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x14)) /* 8 bit DAC using DMA */
{
sb_dsp_command(devc, (unsigned char) (count & 0xff));
@@ -191,7 +192,7 @@
}
else
printk(KERN_WARNING "Sound Blaster: unable to start DAC.\n");
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
devc->intr_active = 1;
}

@@ -213,8 +214,7 @@

devc->irq_mode = IMODE_INPUT;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x24)) /* 8 bit ADC using DMA */
{
sb_dsp_command(devc, (unsigned char) (count & 0xff));
@@ -222,7 +222,7 @@
}
else
printk(KERN_ERR "Sound Blaster: unable to start ADC.\n");
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

devc->intr_active = 1;
}
@@ -258,12 +258,11 @@
sb_devc *devc = audio_devs[dev]->devc;
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x40))
sb_dsp_command(devc, devc->tconst);
sb_dsp_command(devc, DSP_CMD_SPKOFF);
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

devc->trigger_bits = 0;
return 0;
@@ -274,12 +273,11 @@
sb_devc *devc = audio_devs[dev]->devc;
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x40))
sb_dsp_command(devc, devc->tconst);
sb_dsp_command(devc, DSP_CMD_SPKON);
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
devc->trigger_bits = 0;
return 0;
}
@@ -327,10 +325,9 @@
unsigned long flags;
sb_devc *devc = audio_devs[dev]->devc;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
sb_dsp_reset(devc);
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}

/*
@@ -353,8 +350,7 @@

devc->irq_mode = IMODE_OUTPUT;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x48)) /* DSP Block size */
{
sb_dsp_command(devc, (unsigned char) (count & 0xff));
@@ -370,7 +366,7 @@
}
else
printk(KERN_ERR "Sound Blaster: unable to start DAC.\n");
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
devc->intr_active = 1;
}

@@ -393,8 +389,7 @@

devc->irq_mode = IMODE_INPUT;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x48)) /* DSP Block size */
{
sb_dsp_command(devc, (unsigned char) (count & 0xff));
@@ -410,7 +405,7 @@
}
else
printk(KERN_ERR "Sound Blaster: unable to start ADC.\n");
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
devc->intr_active = 1;
}

@@ -484,8 +479,7 @@
if (devc->bits == AFMT_S16_LE)
bits = 0x04; /* 16 bit mode */

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x40))
sb_dsp_command(devc, devc->tconst);
sb_dsp_command(devc, DSP_CMD_SPKOFF);
@@ -493,7 +487,7 @@
sb_dsp_command(devc, 0xa0 | bits); /* Mono input */
else
sb_dsp_command(devc, 0xa8 | bits); /* Stereo input */
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

devc->trigger_bits = 0;
return 0;
@@ -511,8 +505,7 @@
if (devc->model == MDL_SBPRO)
sb_mixer_set_stereo(devc, devc->channels == 2);

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (sb_dsp_command(devc, 0x40))
sb_dsp_command(devc, devc->tconst);
sb_dsp_command(devc, DSP_CMD_SPKON);
@@ -536,7 +529,7 @@
tmp |= 0x02;
sb_setmixer(devc, 0x0e, tmp);
}
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
devc->trigger_bits = 0;
return 0;
}
@@ -706,21 +699,19 @@
}

/* save value */
- save_flags (flags);
- cli ();
+ spin_lock_irqsave(&devc->lock, flags);
bits = devc->bits;
if (devc->fullduplex)
devc->bits = (devc->bits == AFMT_S16_LE) ?
AFMT_U8 : AFMT_S16_LE;
- restore_flags (flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

cnt = count;
if (devc->bits == AFMT_S16_LE)
cnt >>= 1;
cnt--;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);

/* DMAbuf_start_dma (dev, buf, count, DMA_MODE_WRITE); */

@@ -736,7 +727,7 @@

/* restore real value after all programming */
devc->bits = bits;
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}


@@ -768,8 +759,7 @@
cnt >>= 1;
cnt--;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);

/* DMAbuf_start_dma (dev, buf, count, DMA_MODE_READ); */

@@ -783,7 +773,7 @@
sb_dsp_command(devc, (unsigned char) (cnt & 0xff));
sb_dsp_command(devc, (unsigned char) (cnt >> 8));

- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}

static void sb16_audio_trigger(int dev, int bits)
--- linux-2.4.0/drivers/sound/sb_ess.c.orig Fri Jan 26 13:55:19 2001
+++ linux-2.4.0/drivers/sound/sb_ess.c Fri Jan 26 15:17:28 2001
@@ -186,6 +186,7 @@
*/

#include <linux/delay.h>
+#include <linux/spinlock.h>

#include "sound_config.h"
#include "sb_mixer.h"
@@ -524,10 +525,9 @@
unsigned long flags;
sb_devc *devc = audio_devs[dev]->devc;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
sb_dsp_reset(devc);
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

/*
* Audio 2 may still be operational! Creates awful sounds!
@@ -969,8 +969,7 @@
unsigned int val;
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
outb(((unsigned char) (0x40 & 0xff)), MIXER_ADDR);

udelay(20);
@@ -978,7 +977,7 @@
udelay(20);
val |= inb(MIXER_DATA);
udelay(20);
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

return val;
}
@@ -1565,8 +1564,7 @@
printk(KERN_INFO "FKS: write mixer %x: %x\n", port, value);
#endif

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (port >= 0xa0) {
ess_write (devc, port, value);
} else {
@@ -1576,7 +1574,7 @@
outb(((unsigned char) (value & 0xff)), MIXER_DATA);
udelay(20);
};
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}

unsigned int ess_getmixer (sb_devc * devc, unsigned int port)
@@ -1584,8 +1582,7 @@
unsigned int val;
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);

if (port >= 0xa0) {
val = ess_read (devc, port);
@@ -1596,7 +1593,7 @@
val = inb(MIXER_DATA);
udelay(20);
}
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

return val;
}
--- linux-2.4.0/drivers/sound/sb_midi.c.orig Fri Jan 26 13:55:25 2001
+++ linux-2.4.0/drivers/sound/sb_midi.c Fri Jan 26 15:19:01 2001
@@ -11,6 +11,8 @@
* for more info.
*/

+#include <linux/spinlock.h>
+
#include "sound_config.h"

#include "sb.h"
@@ -36,15 +38,14 @@
if (devc == NULL)
return -ENXIO;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
if (devc->opened)
{
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
return -EBUSY;
}
devc->opened = 1;
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

devc->irq_mode = IMODE_MIDI;
devc->midi_broken = 0;
@@ -74,13 +75,12 @@
if (devc == NULL)
return;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
sb_dsp_reset(devc);
devc->intr_active = 0;
devc->input_opened = 0;
devc->opened = 0;
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}

static int sb_midi_out(int dev, unsigned char midi_byte)
@@ -131,14 +131,13 @@
if (devc == NULL)
return;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);

data = inb(DSP_READ);
if (devc->input_opened)
devc->midi_input_intr(devc->my_mididev, data);

- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}

#define MIDI_SYNTH_NAME "Sound Blaster Midi"
--- linux-2.4.0/drivers/sound/sb_common.c.orig Fri Jan 26 13:55:12 2001
+++ linux-2.4.0/drivers/sound/sb_common.c Fri Jan 26 16:50:32 2001
@@ -21,12 +21,16 @@
*
* 2000/09/18 - got rid of attach_uart401
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ * 2001/01/26 - replaced CLI/STI with spinlocks
+ * Chris Rankin <rankinc@zipworld.com.au>
*/

#include <linux/config.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/delay.h>
+#include <linux/spinlock.h>

#include "sound_config.h"
#include "sound_firmware.h"
@@ -62,6 +66,7 @@

static int jazz16_base = 0; /* Not detected */
static unsigned char jazz16_bits = 0; /* I/O relocation bits */
+static spinlock_t jazz16_lock = SPIN_LOCK_UNLOCKED;

/*
* Logitech Soundman Wave specific initialization code
@@ -251,8 +256,7 @@
unsigned long flags;

DDB(printk("Entered dsp_get_vers()\n"));
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
devc->major = devc->minor = 0;
sb_dsp_command(devc, 0xe1); /* Get version */

@@ -269,8 +273,8 @@
}
}
}
+ spin_unlock_irqrestore(&devc->lock, flags);
DDB(printk("DSP version %d.%02d\n", devc->major, devc->minor));
- restore_flags(flags);
}

static int sb16_set_dma_hw(sb_devc * devc)
@@ -368,12 +372,11 @@
/*
* Magic wake up sequence by writing to 0x201 (aka Joystick port)
*/
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&jazz16_lock, flags);
outb((0xAF), 0x201);
outb((0x50), 0x201);
outb((bits), 0x201);
- restore_flags(flags);
+ spin_unlock_irqrestore(&jazz16_lock, flags);
}

static int init_Jazz16(sb_devc * devc, struct address_info *hw_config)
@@ -552,7 +555,9 @@

if (devc->sbmo.acer)
{
- cli();
+ unsigned long flags;
+
+ spin_lock_irqsave(&devc->lock, flags);
inb(devc->base + 0x09);
inb(devc->base + 0x09);
inb(devc->base + 0x09);
@@ -564,7 +569,7 @@
inb(devc->base + 0x0b);
inb(devc->base + 0x09);
inb(devc->base + 0x00);
- sti();
+ spin_unlock_irqrestore(&devc->lock, flags);
}
/*
* Detect the device
@@ -631,7 +636,11 @@
printk(KERN_ERR "sb: Can't allocate memory for device information\n");
return 0;
}
- memcpy((char *) detected_devc, (char *) devc, sizeof(sb_devc));
+ memcpy(detected_devc, devc, sizeof(sb_devc));
+ /*
+ * This "detected_devc" hack is SCARY-ugly! Need to think of a cleaner way!
+ */
+ detected_devc->lock = SPIN_LOCK_UNLOCKED;
MDB(printk(KERN_INFO "SB %d.%02d detected OK (%x)\n", devc->major, devc->minor, hw_config->io_base));
return 1;
}
@@ -937,15 +946,14 @@

if (devc->model == MDL_ESS) return ess_setmixer (devc, port, value);

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);

outb(((unsigned char) (port & 0xff)), MIXER_ADDR);
udelay(20);
outb(((unsigned char) (value & 0xff)), MIXER_DATA);
udelay(20);

- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}

unsigned int sb_getmixer(sb_devc * devc, unsigned int port)
@@ -955,15 +963,14 @@

if (devc->model == MDL_ESS) return ess_getmixer (devc, port);

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);

outb(((unsigned char) (port & 0xff)), MIXER_ADDR);
udelay(20);
val = inb(MIXER_DATA);
udelay(20);

- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

return val;
}
@@ -986,14 +993,13 @@
{
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&jazz16_lock, flags); /* NOT the SB card? */

outb((addr & 0xff), base + 1); /* Low address bits */
outb((addr >> 8), base + 2); /* High address bits */
outb((val), base); /* Data */

- restore_flags(flags);
+ spin_unlock_irqrestore(&jazz16_lock, flags);
}

static unsigned char smw_getmem(sb_devc * devc, int base, int addr)
@@ -1001,14 +1007,13 @@
unsigned long flags;
unsigned char val;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&jazz16_lock, flags); /* NOT the SB card? */

outb((addr & 0xff), base + 1); /* Low address bits */
outb((addr >> 8), base + 2); /* High address bits */
val = inb(base); /* Data */

- restore_flags(flags);
+ spin_unlock_irqrestore(&jazz16_lock, flags);
return val;
}

@@ -1168,12 +1173,11 @@
/*
* Magic wake up sequence by writing to 0x201 (aka Joystick port)
*/
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&jazz16_lock, flags);
outb(0xAF, 0x201);
outb(0x50, 0x201);
outb(bits, 0x201);
- restore_flags(flags);
+ spin_unlock_irqrestore(&jazz16_lock, flags);

hw_config->name = "Jazz16";
smw_midi_init(devc, hw_config);

And for an encore, I noticed that my SoundBlaster module loaded the
uart401 module. So here's a spinlock patch for the uart401:

--- linux-2.4.0/drivers/sound/uart401.c.orig Wed Jan 17 01:24:40 2001
+++ linux-2.4.0/drivers/sound/uart401.c Fri Jan 26 13:51:37 2001
@@ -16,6 +16,7 @@
* Fixed to allow IRQ > 15
* Christoph Hellwig Adapted to module_init/module_exit
* Arnaldo C. de Melo got rid of check_region
+ * Chris Rankin Used spinlocks instead of STI/CLI
*
* Status:
* Untested
@@ -23,6 +24,7 @@

#include <linux/init.h>
#include <linux/module.h>
+#include <linux/spinlock.h>

#include "sound_config.h"

@@ -38,6 +40,7 @@
volatile unsigned char input_byte;
int my_dev;
int share_irq;
+ spinlock_t lock;
}
uart401_devc;

@@ -152,13 +155,12 @@
* Test for input since pending input seems to block the output.
*/

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);

if (input_avail(devc))
uart401_input_loop(devc);

- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

/*
* Sometimes it takes about 13000 loops before the output becomes ready
@@ -222,8 +224,8 @@
int ok, timeout;
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
+
for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);

devc->input_byte = 0;
@@ -237,7 +239,7 @@
if (uart401_read(devc) == MPU_ACK)
ok = 1;

- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);
}

static int reset_uart401(uart401_devc * devc)
@@ -320,11 +322,11 @@
devc->input_byte = 0;
devc->my_dev = 0;
devc->share_irq = 0;
+ devc->lock = SPIN_LOCK_UNLOCKED;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&devc->lock, flags);
ok = reset_uart401(devc);
- restore_flags(flags);
+ spin_unlock_irqrestore(&devc->lock, flags);

if (!ok)
goto cleanup_devc;

Then I got cocky and noticed a CLI/STI pair in the sound_open_dma()
and sound_close_dma() functions. I couldn't identify a device to
associate the spinlock with, and so I made it global:

--- linux-2.4.0/drivers/sound/soundcard.c.orig Tue Sep 26 06:32:54 2000
+++ linux-2.4.0/drivers/sound/soundcard.c Fri Jan 26 15:41:49 2001
@@ -20,6 +20,7 @@
* Richard Gooch : moved common (non OSS-specific) devices to sound_core.c
* Rob Riggs : Added persistent DMA buffers support (1998/10/17)
* Christoph Hellwig : Some cleanup work (2000/03/01)
+ * Chris Rankin : Protect DMA access with a spinlock
*/

#include <linux/config.h>
@@ -44,6 +45,9 @@
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/smp_lock.h>
+#include <linux/spinlock.h>
+
+static spinlock_t dma_lock = SPIN_LOCK_UNLOCKED;

/*
* This ought to be moved into include/asm/dma.h
@@ -672,16 +676,15 @@
printk(KERN_ERR "sound_open_dma: Invalid DMA channel %d\n", chn);
return 1;
}
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&dma_lock, flags);

if (dma_alloc_map[chn] != DMA_MAP_FREE) {
+ spin_unlock_irqrestore(&dma_lock, flags);
printk("sound_open_dma: DMA channel %d busy or not allocated (%d)\n", chn, dma_alloc_map[chn]);
- restore_flags(flags);
return 1;
}
dma_alloc_map[chn] = DMA_MAP_BUSY;
- restore_flags(flags);
+ spin_unlock_irqrestore(&dma_lock, flags);
return 0;
}

@@ -699,16 +702,15 @@
{
unsigned long flags;

- save_flags(flags);
- cli();
+ spin_lock_irqsave(&dma_lock, flags);

if (dma_alloc_map[chn] != DMA_MAP_BUSY) {
+ spin_unlock_irqrestore(&dma_lock, flags);
printk(KERN_ERR "sound_close_dma: Bad access to DMA channel %d\n", chn);
- restore_flags(flags);
return;
}
dma_alloc_map[chn] = DMA_MAP_FREE;
- restore_flags(flags);
+ spin_unlock_irqrestore(&dma_lock, flags);
}

static void do_sequencer_timer(unsigned long dummy)

And THEN I thought that it might be a good idea to put a few "const"
declarations into a few function prototypes. I think that this kind of
stuff doesn't hurt, and might even allow someone (?) to move a few
structs (which shouldn't be changing anyway) into the .text section:

--- linux-2.4.0/drivers/sound/uart401.c.orig Wed Jan 17 01:24:40 2001
+++ linux-2.4.0/drivers/sound/uart401.c Thu Jan 18 01:44:49 2001
@@ -292,7 +292,7 @@
int probe_uart401(struct address_info *hw_config, struct module *owner)
{
uart401_devc *devc;
- char *name = "MPU-401 (UART) MIDI";
+ const char *name = "MPU-401 (UART) MIDI";
int ok = 0;
unsigned long flags;

--- linux-2.4.0/drivers/sound/sound_calls.h.orig Mon Apr 3 08:45:06 2000
+++ linux-2.4.0/drivers/sound/sound_calls.h Thu Jan 18 02:49:24 2001
@@ -80,8 +80,8 @@
/* From soundcard.c */
void request_sound_timer (int count);
void sound_stop_timer(void);
-void conf_printf(char *name, struct address_info *hw_config);
-void conf_printf2(char *name, int base, int irq, int dma, int dma2);
+void conf_printf(const char *name, const struct address_info *hw_config);
+void conf_printf2(const char *name, int base, int irq, int dma, int dma2);

/* From sound_timer.c */
void sound_timer_interrupt(void);
--- linux-2.4.0/drivers/sound/soundcard.c.orig Tue Sep 26 06:32:54 2000
+++ linux-2.4.0/drivers/sound/soundcard.c Thu Jan 18 02:47:36 2001
@@ -745,7 +745,7 @@
del_timer(&seq_timer);;
}

-void conf_printf(char *name, struct address_info *hw_config)
+void conf_printf(const char *name, const struct address_info *hw_config)
{
#ifndef CONFIG_SOUND_TRACEINIT
return;
@@ -765,7 +765,7 @@
#endif
}

-void conf_printf2(char *name, int base, int irq, int dma, int dma2)
+void conf_printf2(const char *name, int base, int irq, int dma, int dma2)
{
#ifndef CONFIG_SOUND_TRACEINIT
return;

--- linux-vanilla/drivers/sound/dev_table.h Fri Aug 11 16:26:43 2000
+++ linux-2.4.0-ac3/drivers/sound/dev_table.h Mon Jan 8 18:59:13 2001
@@ -376,16 +377,16 @@
extern int num_sound_timers;
#endif /* _DEV_TABLE_C_ */

-extern int sound_map_buffer (int dev, struct dma_buffparms *dmap, buffmem_desc *info);
void sound_timer_init (struct sound_lowlev_timer *t, char *name);
-void sound_dma_intr (int dev, struct dma_buffparms *dmap, int chan);

#define AUDIO_DRIVER_VERSION 2
#define MIXER_DRIVER_VERSION 2
-int sound_install_audiodrv(int vers, char *name, struct audio_driver *driver,
+int sound_install_audiodrv(int vers, const char *name,
+ const struct audio_driver *driver,
int driver_size, int flags, unsigned int format_mask,
void *devc, int dma1, int dma2);
-int sound_install_mixer(int vers, char *name, struct mixer_operations *driver,
+int sound_install_mixer(int vers, const char *name,
+ const struct mixer_operations *driver,
int driver_size, void *devc);

void sound_unload_audiodev(int dev);
--- linux-vanilla/drivers/sound/dev_table.c Mon Sep 25 20:32:54 2000
+++ linux-2.4.0-ac3/drivers/sound/dev_table.c Mon Jan 8 19:54:48 2001
@@ -16,7 +16,8 @@
#define _DEV_TABLE_C_
#include "sound_config.h"

-int sound_install_audiodrv(int vers, char *name, struct audio_driver *driver,
+int sound_install_audiodrv(int vers, const char *name,
+ const struct audio_driver *driver,
int driver_size, int flags, unsigned int format_mask,
void *devc, int dma1, int dma2)
{
@@ -48,14 +49,14 @@
sound_unload_audiodev(num);
return -(ENOMEM);
}
- memset((char *) op, 0, sizeof(struct audio_operations));
+ memset(op, 0, sizeof(struct audio_operations));
init_waitqueue_head(&op->in_sleeper);
init_waitqueue_head(&op->out_sleeper);
init_waitqueue_head(&op->poll_sleeper);
if (driver_size < sizeof(struct audio_driver))
- memset((char *) d, 0, sizeof(struct audio_driver));
+ memset(d, 0, sizeof(struct audio_driver));

- memcpy((char *) d, (char *) driver, driver_size);
+ memcpy(d, driver, driver_size);

op->d = d;
l = strlen(name) + 1;
@@ -78,7 +79,8 @@
return num;
}

-int sound_install_mixer(int vers, char *name, struct mixer_operations *driver,
+int sound_install_mixer(int vers, const char *name,
+ const struct mixer_operations *driver,
int driver_size, void *devc)
{
struct mixer_operations *op;
@@ -107,8 +109,8 @@
printk(KERN_ERR "Sound: Can't allocate mixer driver for (%s)\n", name);
return -ENOMEM;
}
- memset((char *) op, 0, sizeof(struct mixer_operations));
- memcpy((char *) op, (char *) driver, driver_size);
+ memset(op, 0, sizeof(struct mixer_operations));
+ memcpy(op, driver, driver_size);

l = strlen(name) + 1;
if (l > sizeof(op->name))

OK, that's all. I think that the const-stuff is trivial in the sense
that once the function bodies compile then you're home and dry because
their callers don't care. I'm more concerned about the spinlock stuff
- would 2.4's improved locking scheme make some of them completely
redundant anyway?

Cheers,
Chris

-
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