From 4e637d2bf65c1090f737fae57c903f2ea93e907e Mon Sep 17 00:00:00 2001
From: Daniel Koepping <elkoled@gmail.com>
Date: Mon, 5 Oct 2026 15:31:58 -0700
Subject: [PATCH] Revert #38464 (#39038)

* Revert #38464

Reverts aa0ac919baa0df2fa792e281246d4a1a1e6a1652.

Original-upstream-commit: 910c08e0828c54ce7919ae14606166779a52bf94
Upstream: https://github.com/commaai/openpilot/commit/910c08e0828c54ce7919ae14606166779a52bf94
---
 openpilot/selfdrive/pandad/spi.cc | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/openpilot/selfdrive/pandad/spi.cc b/openpilot/selfdrive/pandad/spi.cc
index 369032a533..f54c26e506 100644
--- a/openpilot/selfdrive/pandad/spi.cc
+++ b/openpilot/selfdrive/pandad/spi.cc
@@ -29,12 +29,6 @@ enum SpiError {
 
 const unsigned int SPI_ACK_TIMEOUT = 500; // milliseconds
 const std::string SPI_DEVICE = "/dev/spidev0.0";
-// TODO: fix SPI turnaround synchronization at the protocol level.
-static uint64_t spi_last_bus_activity_ns = 0;  // protected by hw_lock
-
-static void wait_for_spi_turnaround(uint64_t start_ns) {
-  while ((nanos_since_boot() - start_ns) < 400000) {}
-}
 
 class LockEx {
 public:
@@ -325,8 +319,6 @@ int PandaSpiHandle::spi_transfer(uint8_t endpoint, uint8_t *tx_data, uint16_t tx
   assert(tx_len < SPI_BUF_SIZE);
   assert(max_rx_len < SPI_BUF_SIZE);
 
-  wait_for_spi_turnaround(spi_last_bus_activity_ns);
-
   xfer_count++;
   header = {
     .sync = SPI_SYNC,
@@ -355,7 +347,6 @@ int PandaSpiHandle::spi_transfer(uint8_t endpoint, uint8_t *tx_data, uint16_t tx
   if (ret < 0) {
     goto fail;
   }
-  wait_for_spi_turnaround(nanos_since_boot());
 
   // Send data
   if (tx_data != NULL) {
@@ -398,7 +389,6 @@ int PandaSpiHandle::spi_transfer(uint8_t endpoint, uint8_t *tx_data, uint16_t tx
     memcpy(rx_data, rx_buf + 3, rx_data_len);
   }
 
-  spi_last_bus_activity_ns = nanos_since_boot();
   return rx_data_len;
 
 fail:
@@ -413,7 +403,6 @@ fail:
     }
   }
 
-  spi_last_bus_activity_ns = nanos_since_boot();
   if (ret >= 0) ret = -1;
   return ret;
 }