[Intel-wired-lan] [PATCH] e1000e: Add "cnp" PCH boards to the packet loss fixing workaround

[Neftin, Sasha]

On 5/14/2023 12:34, kovalev at altlinux.org wrote:
> From: Vasiliy Kovalev <kovalev at altlinux.org>
> 
> Add CannonLake and some Comet Lake Client Platform into the range
> of workaround for packet loss issue.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=217436
> Fixes: 639e298f432fb0 ("e1000e: Fix packet loss on Tiger Lake and later")
> Signed-off-by: Vasiliy Kovalev <kovalev at altlinux.org>
> ---
>   drivers/net/ethernet/intel/e1000e/ich8lan.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
> index 9466f65a6da77..e233a0b93bcf1 100644
> --- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
> +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
> @@ -4875,7 +4875,7 @@ static s32 e1000_init_hw_ich8lan(struct e1000_hw *hw)
>   	/* Enable workaround for packet loss issue on TGP PCH
%s/TGP/CMP - In case we go in this direction.
>   	 * Do not gate DMA clock from the modPHY block
>   	 */
> -	if (mac->type >= e1000_pch_tgp) {
> +	if (mac->type >= e1000_pch_cnp) {
>   		fflt_dbg = er32(FFLT_DBG);
>   		fflt_dbg |= E1000_FFLT_DBG_DONT_GATE_WAKE_DMA_CLK;
>   		ew32(FFLT_DBG, fflt_dbg);
It is a bit better. Let's clarify a few points before continuing.
1. I realized all components on your board are ADL-P. (lspci_npk.txt). I 
now aware (I will ask around) about combination of ADL and old 1Gbe 
controller.
Where did you get this board? My concern is that the wrong BIOS/IFWI is 
in use for this platform. 1Gbe controller may come up with corrupted 
initial HW values. (NVM of controller is corrupted, in this case, we 
will face a much worst platform behavior)

2. Need confirmation that writing to the 'FFLT_DBG' register is harmless 
for the CML platform.