From 2cf721db4b78c11cb57d5a30888eb25ca04d9a29 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 10 Dec 2015 16:49:36 +0100 Subject: [PATCH] ALSA: hda - Increase default bdl_pos_adj for Baytrail/Braswell Intel Atom processors seem to have a problem at recording when bdl_pos_adj is set to an odd value. When a value like 1 is used, it may drop the samples unexpectedly. Actually, for the old Atoms, we used to set AZX_DRIVER_SCH type, and this assigns 32 as default. Meanwhile the newer chips, Baytrail and Braswell, are set as AZX_DRIVER_PCH, and the lower default value, 1, is assigned. This patch changes the default values for these chipsets to a safer default, 32, again. Since changing the driver type (AZX_DRIVER_XXX) leads to the rename of the driver string, it would result in a possible regression. So, we can't change the type. Instead, in this patch, manual (ugly) PCI ID checks are added on top. A drawback by this increase is the slight increase of the latency, but it's a sub-ms order in normal situations, so mostly negligible. Reported-and-tested-by: Jochen Henneberg Signed-off-by: Takashi Iwai --- sound/pci/hda/hda_intel.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index a17bf0467edc..56ef6b6fb546 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -1490,6 +1490,15 @@ static void azx_probe_work(struct work_struct *work) static int default_bdl_pos_adj(struct azx *chip) { + /* some exceptions: Atoms seem problematic with value 1 */ + if (chip->pci->vendor == PCI_VENDOR_ID_INTEL) { + switch (chip->pci->device) { + case 0x0f04: /* Baytrail */ + case 0x2284: /* Braswell */ + return 32; + } + } + switch (chip->driver_type) { case AZX_DRIVER_ICH: case AZX_DRIVER_PCH: -- 2.20.1