Messages in this thread | | | Subject | Re: [PATCH v2 2/2] ALSA: hda/tegra: fix tegra-hda on tegra30 soc | From | Sameer Pujar <> | Date | Fri, 8 Jan 2021 20:45:39 +0530 |
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On 1/8/2021 7:29 PM, 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. > > 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 > > The tegra-hda device was introduced in tegra30 but only utilized in > tegra124 until recent chips. Tegra210/186 work only due to a hardware > change. For this reason it is unknown when this issue first manifested. > Discussions with the hardware team show this applies to all current tegra > chips. It has been resolved in the tegra234, which does not have hda > support at this time. > > The explanation from the hardware team is this: > Below is the striping formula referenced from HD audio spec. > { ((num_channels * bits_per_sample) / number of SDOs) >= 8 } > > The current issue is seen because Tegra HW has a problem with boundary > condition (= 8) for striping. The reason why it is not seen on > Tegra210/Tegra186 is because it uses max 2SDO lines. Max SDO lines is > read from GCAP register. > > For the given stream (channels = 2, bps = 16); > ratio = (channels * bps) / NSDO = 32 / NSDO; > > On Tegra30, ratio = 32/4 = 8 (FAIL) > On Tegra210/186, ratio = 32/2 = 16 (PASS) > On Tegra194, ratio = 32/4 = 8 (FAIL) ==> Earlier workaround was > applied for it > > If Tegra210/186 is forced to use 4SDO, it fails there as well. So the > behavior is consistent across all these chips. > > Applying the fix in [1] universally resolves this issue on tegra30-hda. > Tested on the Ouya game console and the tf201 tablet. > > [1] commit 60019d8c650d ("ALSA: hda/tegra: workaround playback failure on > Tegra194") > > Reviewed-by: Jon Hunter <jonathanh@nvidia.com> > Tested-by: Ion Agorria <ion@agorria.com> > Signed-off-by: Peter Geis <pgwipeout@gmail.com> > --- > sound/pci/hda/hda_tegra.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)
Thanks Peter.
Reviewed-by: Sameer Pujar <spujar@nvidia.com>
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