Dear Vitaly,

Thank you for your patch.

Am 06.01.26 um 15:14 schrieb Vitaly Lifshits:
Panther Lake systems introduced an autonomous power gating feature for
the integrated Gigabit Ethernet in shutdown state (S5) state. As part of
it, the reset value of DPG_EN bit was changed to 1. Clear this bit after
performing hardware reset to avoid errors such as Tx/Rx hangs, or packet
loss/corruption.

Fixes: 0c9183ce61bc ("e1000e: Add support for the next LOM generation")
Signed-off-by: Vitaly Lifshits <[email protected]>
---
v4: fix commit message
v3: rephrase a comment in the code
v2: fix a typo in a macro
v1: initial version
---
  drivers/net/ethernet/intel/e1000e/ich8lan.c | 10 ++++++++++
  2 files changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/intel/e1000e/defines.h 
b/drivers/net/ethernet/intel/e1000e/defines.h
index ba331899d186..d4a1041e456d 100644
--- a/drivers/net/ethernet/intel/e1000e/defines.h
+++ b/drivers/net/ethernet/intel/e1000e/defines.h
@@ -33,6 +33,7 @@
/* Extended Device Control */
  #define E1000_CTRL_EXT_LPCD  0x00000004     /* LCD Power Cycle Done */
+#define E1000_CTRL_EXT_DPG_EN  0x00000008 /* Dynamic Power Gating Enable */
  #define E1000_CTRL_EXT_SDP3_DATA 0x00000080 /* Value of SW Definable Pin 3 */
  #define E1000_CTRL_EXT_FORCE_SMBUS 0x00000800 /* Force SMBus mode */
  #define E1000_CTRL_EXT_EE_RST    0x00002000 /* Reinitialize from EEPROM */
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c 
b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index eead80bba6f4..13841daba399 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -4932,6 +4932,16 @@ static s32 e1000_reset_hw_ich8lan(struct e1000_hw *hw)
        reg |= E1000_KABGTXD_BGSQLBIAS;
        ew32(KABGTXD, reg);
+ /*
+        * The hardware reset value of the DPG_EN bit is 1.
+        * Clear DPG_EN to prevent unexpected autonomous power gating.
+        */
+       if (hw->mac.type >= e1000_pch_ptp) {
+               reg = er32(CTRL_EXT);
+               reg &= ~E1000_CTRL_EXT_DPG_EN;
+               ew32(CTRL_EXT, reg);
+       }
+
        return 0;
  }

Reviewed-by: Paul Menzel <[email protected]>


Kind regards,

Paul

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