Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/perex/alsa

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/perex/alsa: (299 commits)
  [ALSA] version 1.0.16rc2
  [ALSA] hda: fix Mic in as output
  [ALSA] emu10k1 - Another EMU0404 Board ID
  [ALSA] emu10k1 - Fix kthread handling at resume
  [ALSA] emu10k1: General cleanup, add new locks, fix alsa bug#3501, kernel bug#9304.
  [ALSA] emu10k1 - Use enum for emu_model types
  [ALSA] emu10k1 - Don't create emu1010 controls for non-emu boards
  [ALSA] emu10k1 - 1616(M) cardbus improvements
  [ALSA] snd:emu10k1: E-Mu updates. Fixes to firmware loading and support for 0404.
  [ALSA] emu10k1: Add comments regarding E-Mu ins and outs.
  [ALSA] oxygen: revert SPI clock frequency change for AK4396/WM8785
  [ALSA] es1938 - improve capture hw pointer reads
  [ALSA] HDA-Intel - Add support for Intel SCH
  [ALSA] hda: Add GPIO mute support to STAC9205
  [ALSA] hda-codec - Add Dell T3400 support
  [ALSA] hda-codec - Add model for HP DV9553EG laptop
  [ALSA] hda-codec - Control SPDIF as slave
  [ALSA] hda_intel: ALSA HD Audio patch for Intel ICH10 DeviceID's
  [ALSA] Fix Oops with PCM OSS sync
  [ALSA] hda-codec - Add speaker automute to ALC262 HP models
  ...

1 files changed, 25 insertions, 3 deletions

diff --git a/sound/pci/es1938.c b/sound/pci/es1938.c
index fb25abe68a0..1a314fa99c4 100644
--- a/sound/pci/es1938.c
+++ b/sound/pci/es1938.c
@@ -47,7 +47,6 @@
 */
 
 
-#include <sound/driver.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/pci.h>
@@ -227,6 +226,7 @@ struct es1938 {
 	unsigned int dma2_start;
 	unsigned int dma1_shift;
 	unsigned int dma2_shift;
+	unsigned int last_capture_dmaaddr;
 	unsigned int active;
 
 	spinlock_t reg_lock;
@@ -529,6 +529,7 @@ static void snd_es1938_capture_setdma(struct es1938 *chip)
 	outb(1, SLDM_REG(chip, DMAMASK));
 	outb(0x14, SLDM_REG(chip, DMAMODE));
 	outl(chip->dma1_start, SLDM_REG(chip, DMAADDR));
+	chip->last_capture_dmaaddr = chip->dma1_start;
 	outw(chip->dma1_size - 1, SLDM_REG(chip, DMACOUNT));
 	/* 3. Unmask DMA */
 	outb(0, SLDM_REG(chip, DMAMASK));
@@ -770,19 +771,40 @@ static int snd_es1938_playback_prepare(struct snd_pcm_substream *substream)
 	return -EINVAL;
 }
 
+/* during the incrementing of dma counters the DMA register reads sometimes
+   returns garbage. To ensure a valid hw pointer, the following checks which
+   should be very unlikely to fail are used:
+   - is the current DMA address in the valid DMA range ?
+   - is the sum of DMA address and DMA counter pointing to the last DMA byte ?
+   One can argue this could differ by one byte depending on which register is
+   updated first, so the implementation below allows for that.
+*/
 static snd_pcm_uframes_t snd_es1938_capture_pointer(struct snd_pcm_substream *substream)
 {
 	struct es1938 *chip = snd_pcm_substream_chip(substream);
 	size_t ptr;
+#if 0
 	size_t old, new;
-#if 1
 	/* This stuff is *needed*, don't ask why - AB */
 	old = inw(SLDM_REG(chip, DMACOUNT));
 	while ((new = inw(SLDM_REG(chip, DMACOUNT))) != old)
 		old = new;
 	ptr = chip->dma1_size - 1 - new;
 #else
-	ptr = inl(SLDM_REG(chip, DMAADDR)) - chip->dma1_start;
+	size_t count;
+	unsigned int diff;
+
+	ptr = inl(SLDM_REG(chip, DMAADDR));
+	count = inw(SLDM_REG(chip, DMACOUNT));
+	diff = chip->dma1_start + chip->dma1_size - ptr - count;
+
+	if (diff > 3 || ptr < chip->dma1_start
+	      || ptr >= chip->dma1_start+chip->dma1_size)
+	  ptr = chip->last_capture_dmaaddr;            /* bad, use last saved */
+	else
+	  chip->last_capture_dmaaddr = ptr;            /* good, remember it */
+
+	ptr -= chip->dma1_start;
 #endif
 	return ptr >> chip->dma1_shift;
 }