> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf
> Of Vitaly Lifshits
> Sent: Tuesday, December 23, 2025 10:51 AM
> To: [email protected]
> Cc: Lifshits, Vitaly <[email protected]>
> Subject: [Intel-wired-lan] [PATCH iwl-net v1 2/2] e1000e: clear DPG_EN
> after reset to avoid autonomous power-gating
>
> 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]>
> ---
> drivers/net/ethernet/intel/e1000e/ich8lan.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c
> b/drivers/net/ethernet/intel/e1000e/ich8lan.c
> index eead80bba6f4..dbf240c8b483 100644
> --- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
> +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
> @@ -4932,6 +4932,15 @@ static s32 e1000_reset_hw_ich8lan(struct
> e1000_hw *hw)
> reg |= E1000_KABGTXD_BGSQLBIAS;
> ew32(KABGTXD, reg);
>
> + /* The reset value of DPG_EN bit was changed to 1
The opening /* should not have text on the same line for multi-line comments,
am I wrong?
But short one line C comment /* ... */ could be better.
> + * clear it to avoid unexpected autonomous power-gating
> + */
> + if (hw->mac.type >= e1000_pch_ptp) {
> + reg = er32(CTRL_EXT);
> + reg &= ~E1000_CTRL_EXT;
The mask E1000_CTRL_EXT is applied to clear bits, but E1000_CTRL_EXT is the
register name, not a bit mask!
#define E1000_CTRL_EXT 0x00018 /* Extended Device Control - RW */
> + ew32(CTRL_EXT, reg);
> + }
> +
> return 0;
> }
>
BTW doublecheck you don't use spaces instead of tabs.
With the best regards
Alex
> --
> 2.34.1
