Re: [PATCH 1/5] phy: qcom: qmp-pcie: Skip PHY reset if already up

[Konrad Dybcio]

On 2/16/26 3:53 PM, Manivannan Sadhasivam wrote:
> On Fri, Jan 09, 2026 at 04:03:37PM +0200, Dmitry Baryshkov wrote:
>> On Fri, Jan 09, 2026 at 02:10:49PM +0100, Neil Armstrong wrote:
>>> On 1/9/26 14:08, Dmitry Baryshkov wrote:
>>>> On Fri, Jan 09, 2026 at 12:51:06PM +0530, Krishna Chaitanya Chundru wrote:
>>>>> If the bootloader has already powered up the PCIe PHY, doing a full
>>>>> reset and waiting for it to come up again slows down boot time.
>>>>
>>>> How big is the delay caused by it?
>>>>
>>>>>
>>>>> Add a check for PHY status and skip the reset steps when the PHY is
>>>>> already active. In this case, only enable the required resources during
>>>>> power-on. This works alongside the existing logic that skips the init
>>>>> sequence.
>>>>
>>>> Can we end up in a state where the bootloader has mis-setup the link? Or
>>>> the link going bad because of any glitch during the bootup?
>>>
>>> Good question, can we add a module parameter to force a full reset of the PHY in case
>>> the bootloader is buggy ?
>>
>> I'd suggest a simpler thing: if the reset was skipped, reset the PHY in
>> case of an error and retry. That's also one of the reasons why I asked
>> for skip_reset not to be the persistent value.
>>
> 
> I'm not sure what value would resetting the PHY provide in the case of failure.
> As per this patch, skip_reset is only going to be set for platforms where
> bootloader has already configured the PHY. So in the case of PHY link failure,
> simply resetting the PHY won't help IMO as the PHY register contents are going
> to be presistent due to nocsr_reset.

We can pull the not-nocsr_reset though?

Konrad