Re: [PATCH] scsi: ufs: qcom: Drop the PHY power_count check

[Manivannan Sadhasivam]

On Wed, Mar 25, 2026 at 02:29:22PM +0200, Vladimir Oltean wrote:
> On Wed, Mar 25, 2026 at 05:31:22PM +0530, Manivannan Sadhasivam wrote:
> > phy_power_off() can safely be called even when PHY is not powered on. So
> > drop the PHY power_count check.
> 
> Sorry, do you mind writing a more elaborate explanation _why_ you think
> that phy_power_off() can safely be called even when the PHY is not
> powered on? If 0, the power_count would become negative after
> phy_power_off(), and a subsequent phy_power_on() would merely bump it
> back to 0, thereby not calling into the driver's qmp_ufs_power_on().
> If there is a regulator assigned to phy->pwr, this would see a call to
> regulator_disable() with no prior call having been made to regulator_enable().
> At the very least you'd want to explain in the commit message why that
> is something to be desired, so as to give reviewers confidence that
> conscientious thought has been given to the change.

Sorry, I just rushed through it. So far in my tests, phy_power_on() gets called
first, before phy_power_off() in ufs_qcom_power_up_sequence(), so I mistakenly
thought that the clk, regulator disable APIs will silently bail out if not
enabled earlier. But I was wrong as they will just scream out loudly with
WARN() and that's too bad.

Though I couldn't trigger that in my tests, I'm still not 100% sure about that.
So let's drop this patch and proceed with your state tracking patch instead.

Apologies for the noise!

- Mani

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