Re: [PATCH 2/2] ALSA: hda/tegra: fix tegra-hda on tegra30 soc

From: Sameer Pujar
Date: Tue Jan 05 2021 - 01:31:42 EST




On 12/25/2020 6:50 AM, Peter Geis wrote:
External email: Use caution opening links or attachments


Currently hda on tegra30 fails to open a stream with an input/output error.
This is similar to the issue referenced in [1].

For example:
speaker-test -Dhw:0,3 -c 2

speaker-test 1.2.2

Playback device is hw:0,3
Stream parameters are 48000Hz, S16_LE, 2 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 64 to 16384
Period size range from 32 to 8192
Using max buffer size 16384
Periods = 4
was set period_size = 4096
was set buffer_size = 16384
0 - Front Left
Write error: -5,Input/output error
xrun_recovery failed: -5,Input/output error
Transfer failed: Input/output error

[1] states "Due to a legacy HW design problem", implying the issue applies to all previous tegra-hda devices.
The tegra-hda device was introduced in tegra30 but only utilized in tegra124 until now.
For this reason it is unknown when this issue first manifested.

Applying the fix in [1] universally resolves this issue on tegra30.
Tested on the Ouya game console and the tf201 tablet.

[1] 60019d8c650d ("ALSA: hda/tegra: workaround playback failure on Tegra194")

This issue was never seen on Tegra210/Tegra186 and hence at that time it was thought to be specific to Tegra194. I never tested this on Tegra30 since I don't have this device. I will clarify this with HW folks if workaround is safer for all chips.


Signed-off-by: Peter Geis <pgwipeout@xxxxxxxxx>
Tested-by: Ion Agorria <ion@xxxxxxxxxxx>
---
sound/pci/hda/hda_tegra.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/sound/pci/hda/hda_tegra.c b/sound/pci/hda/hda_tegra.c
index 70164d1428d4..f8d61e677a09 100644
--- a/sound/pci/hda/hda_tegra.c
+++ b/sound/pci/hda/hda_tegra.c
@@ -388,8 +388,7 @@ static int hda_tegra_first_init(struct azx *chip, struct platform_device *pdev)
* in powers of 2, next available ratio is 16 which can be
* used as a limiting factor here.
*/
- if (of_device_is_compatible(np, "nvidia,tegra194-hda"))
- chip->bus.core.sdo_limit = 16;
+ chip->bus.core.sdo_limit = 16;

Future Tegra chips address this problem and hence cannot be enforced by default. May be we can have like below:

if (of_device_is_compatible(np, "nvidia,tegra30-hda"))
chip->bus.core.sdo_limit = 16;


/* codec detection */
if (!bus->codec_mask) {
--
2.25.1