[alsa-devel] omap-mcbsp: TX Buffer Overflow
Hi,
we have AM3703 based board similar to BeagleBoard. I'm hitting this error after upgrade to latest LTS 4.19.71 (upgraded from 4.1):
omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!
This appears during or after playing of short (~2s) ding-dong wav. That error exists for longer time, because handling of tx buffer overflow irq was introduced in 2016: 4e85e7776eba ("ASoC: omap-mcbsp: Enable TX/RX under and overflow interrupts"). I've cherry-picked it to 4.1 and I see the error there also. The sound seems clear and ok to me, but we are using low quality speaker.
There are two workarounds to get rid of the message: 1) Change 'dma_op_mode' sysfs attribute from 'element' to 'threshold'. I found that just by coincidence when checking sysfs attributes. 2) Compile kernel with CONFIG_VIDEO_OMAP3=y. Found on Logic PD forum [1].
Does anybody have any idea what's going wrong? Or why these (somehow) unrelated workarounds help?
Thanks,
Tomas
[1] https://support.logicpd.com/TDGForum/tabid/124/aft/2277/Default.aspx
On Fri, Sep 06, 2019 at 04:51:09PM +0200, Tomas Novotny wrote:
Hi,
we have AM3703 based board similar to BeagleBoard. I'm hitting this error after upgrade to latest LTS 4.19.71 (upgraded from 4.1):
omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!
This appears during or after playing of short (~2s) ding-dong wav. That error exists for longer time, because handling of tx buffer overflow irq was introduced in 2016: 4e85e7776eba ("ASoC: omap-mcbsp: Enable TX/RX under and overflow interrupts"). I've cherry-picked it to 4.1 and I see the error there also. The sound seems clear and ok to me, but we are using low quality speaker.
Just FYI, for stream capture there's omap-mcbsp 49022000.mcbsp: RX Buffer Underflow!
As far as I remember all stable kernels we have in production - 4.9.x, 4.14.x and 4.19.x - are affected. IGEPv2 with both DM3730 and OMAP3530 are affected (headless machines, CONFIG_VIDEO_OMAP3=n).
And DT is probably worth updating: omap_hwmod: mcbsp2_sidetone using broken dt data from mcbsp omap_hwmod: mcbsp3_sidetone using broken dt data from mcbsp
I never motivated myself to dig deeper as catured stream looks pretty normal.
l.
There are two workarounds to get rid of the message:
- Change 'dma_op_mode' sysfs attribute from 'element' to 'threshold'. I
found that just by coincidence when checking sysfs attributes. 2) Compile kernel with CONFIG_VIDEO_OMAP3=y. Found on Logic PD forum [1].
Does anybody have any idea what's going wrong? Or why these (somehow) unrelated workarounds help?
Thanks,
Tomas
[1] https://support.logicpd.com/TDGForum/tabid/124/aft/2277/Default.aspx
* Ladislav Michl ladis@linux-mips.org [190907 09:14]:
On Fri, Sep 06, 2019 at 04:51:09PM +0200, Tomas Novotny wrote:
Hi,
we have AM3703 based board similar to BeagleBoard. I'm hitting this error after upgrade to latest LTS 4.19.71 (upgraded from 4.1):
omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!
This appears during or after playing of short (~2s) ding-dong wav. That error exists for longer time, because handling of tx buffer overflow irq was introduced in 2016: 4e85e7776eba ("ASoC: omap-mcbsp: Enable TX/RX under and overflow interrupts"). I've cherry-picked it to 4.1 and I see the error there also. The sound seems clear and ok to me, but we are using low quality speaker.
Just FYI, for stream capture there's omap-mcbsp 49022000.mcbsp: RX Buffer Underflow!
As far as I remember all stable kernels we have in production - 4.9.x, 4.14.x and 4.19.x - are affected. IGEPv2 with both DM3730 and OMAP3530 are affected (headless machines, CONFIG_VIDEO_OMAP3=n).
Hmm I wonder if this is still related to the SoC idling? See commit 9834ffd1ecc3 ("ASoC: omap-mcbsp: Add PM QoS support for McBSP to prevent glitches"), maybe something still needs to be fixed in that area.
And DT is probably worth updating: omap_hwmod: mcbsp2_sidetone using broken dt data from mcbsp omap_hwmod: mcbsp3_sidetone using broken dt data from mcbsp
I never motivated myself to dig deeper as catured stream looks pretty normal.
These mean the devices should really have separate nodes in the dts rather than combining multiple devices into a single node with multiple reg entries.
The issue with combining multiple devices into a single device is that flushing posted write with a read back to one register range will not flush it for the other which can cause mysterious bugs.
Regards,
Tony
Hi Tony,
On Mon, 9 Sep 2019 09:24:07 -0700 Tony Lindgren tony@atomide.com wrote:
- Ladislav Michl ladis@linux-mips.org [190907 09:14]:
On Fri, Sep 06, 2019 at 04:51:09PM +0200, Tomas Novotny wrote:
Hi,
we have AM3703 based board similar to BeagleBoard. I'm hitting this error after upgrade to latest LTS 4.19.71 (upgraded from 4.1):
omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!
This appears during or after playing of short (~2s) ding-dong wav. That error exists for longer time, because handling of tx buffer overflow irq was introduced in 2016: 4e85e7776eba ("ASoC: omap-mcbsp: Enable TX/RX under and overflow interrupts"). I've cherry-picked it to 4.1 and I see the error there also. The sound seems clear and ok to me, but we are using low quality speaker.
Just FYI, for stream capture there's omap-mcbsp 49022000.mcbsp: RX Buffer Underflow!
As far as I remember all stable kernels we have in production - 4.9.x, 4.14.x and 4.19.x - are affected. IGEPv2 with both DM3730 and OMAP3530 are affected (headless machines, CONFIG_VIDEO_OMAP3=n).
Hmm I wonder if this is still related to the SoC idling? See commit 9834ffd1ecc3 ("ASoC: omap-mcbsp: Add PM QoS support for McBSP to prevent glitches"), maybe something still needs to be fixed in that area.
I also found the cpuidle information somewhere, but CPU_IDLE=n (and let PM=y) didn't help me. I'm speaking just for playback. I can do some better test if you want.
Thanks,
Tomas
And DT is probably worth updating: omap_hwmod: mcbsp2_sidetone using broken dt data from mcbsp omap_hwmod: mcbsp3_sidetone using broken dt data from mcbsp
I never motivated myself to dig deeper as catured stream looks pretty normal.
These mean the devices should really have separate nodes in the dts rather than combining multiple devices into a single node with multiple reg entries.
The issue with combining multiple devices into a single device is that flushing posted write with a read back to one register range will not flush it for the other which can cause mysterious bugs.
Regards,
Tony
participants (3)
-
Ladislav Michl -
Tomas Novotny -
Tony Lindgren