Touchpad erase not performed correctly!

[hughsie]

I'm reading the source code of the touchpad firmware, and noticed in write_tp_fw:

rc = try_touchpad_verify(ICERASE, ICERASE_PASS, 0);
if (rc < 0) {
    printf(">>> Touchpad erase failed\n");
    goto finish;
}

Looking at the definition on try_touchpad_verify, i see:

int try_touchpad_verify(int type, int pass, int sendcmd)

so sendcmd=0... This is passed to touchpad_verify() which only does the SetReport when sendcmd is nonzero -- at the moment the code is just reading back the status 100 times and I guess by luck one of those times getting the expected ICERASE_PASS=0xE2 value.

This seems to explain quite a few people having TP flash failures, with the 2nd step failing on Touchpad erase failed. If this analysis is correct, it should be a simple case of:

-rc = try_touchpad_verify(ICERASE, ICERASE_PASS, 0);
+rc = try_touchpad_verify(ICERASE, ICERASE_PASS, 1);

...and I'd be happy to do a PR if that sounds acceptable. Not tested on actual hardware, as my PBP is waiting in customs.

Other people hitting this problem:

• https://forum.pine64.org/showthread.php?tid=8875
• https://forum.pine64.org/showthread.php?tid=8407&pid=56570
• https://archived.forum.manjaro.org/t/how-to-flash-new-keyboard-touchpad-firmware-on-pinebook-pro/112366/4

Richard.