TPS65988: DP Alt Mode Sink doesn't send USB-PD messages after sending 2.2 ms HPD pulse

Andrey Ilves

Part Number: TPS65988
Other Parts Discussed in Thread: TPS65987, TPS65987D

Hi,

We use TPS65988DH chip with port 2 setup as DisplayPort Sink, GPIO4 is used as HPD input.
Our DP sink generates HPD pulse with different width and sends it to GPIO4 HPD input. If pulse width is more than 4 ms, tps65988 transmits USB-PD message with Alt DP Attention command. But after sending a HPD with pulse width 2.2 ms, tps65988 will not transmit any USB-PD message with Alt DP Attention command any more.
To restore functionality need to power cycle or issue GAID command.

The problem looks very similar to
e2e.ti.com/.../tps65988-dp-alt-mode-sink-gets-stuck-after-sending-4-and-4-8-millisecond-hpd-pulse

Has this problem been solved already?

over 4 years ago

0 Adam Mc Gaffin over 4 years ago

TI__Mastermind 30000 points

Hi Andrey,

No, this item is still being investigated internally. In the mean time, I would recommend using a HPD pulse width longer than 4ms.

0 Mark Stockfisch over 4 years ago in reply to Adam Mc Gaffin

Prodigy 115 points

Hi Adam,

When might we expect a solution to these problems. I note that he current base firmware we are using (TPS65987_88_F707_10_08.bin) has not been updated since 2019-11-10. Is there newer base firmware that we can try?

0 Adam Mc Gaffin over 4 years ago in reply to Mark Stockfisch

TI__Mastermind 30000 points

Hi Mark,

Our team is still looking into this item. Firmware version TPS65987_88_F707_10_08 is still the latest firmware version for the TPS65987D and TPS65988. I do not have a date at this moment when this item will be resolved.

Is this item gating further validation or production? As I mentioned in the previous comment, I would recommend using an HPD pulse width longer than 4ms until this item is resolved

0 Mark Stockfisch over 4 years ago in reply to Adam Mc Gaffin

Prodigy 115 points

Hi Adam,

Thanks for the update.

Unfortunately, we are using your chip in test equipment that executes the VESA compliance test. That test specifies 4ms (see Section 4.2.1.3 of the DisplayPort v1.4a Link Compliance Test (r1.0 2020) test case 1d). Therefore, we don't have the option of choosing a different pulse width.

0 Adam Mc Gaffin over 4 years ago in reply to Mark Stockfisch

TI__Mastermind 30000 points

Hi Mark,

Thank you for the additional information. I'll take this info to the team and update you soon

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TPS65988: DP Alt Mode Sink doesn't send USB-PD messages after sending 2.2 ms HPD pulse