Re: [PATCH] ufs: core: Initialize a variable mode for PA_PWRMODE

[Bart Van Assche]

On 10/13/25 1:20 AM, Wonkon Kim wrote:
> > On 10/2/25 12:00 AM, Wonkon Kim wrote:
> > >    static bool ufshcd_is_pwr_mode_restore_needed(struct ufs_hba *hba)
> > >    {
> > >    	struct ufs_pa_layer_attr *pwr_info = &hba->pwr_info;
> > > -	u32 mode;
> > > +	u32 mode = 0;
> > >
> > >    	ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PWRMODE), &mode);
> >
> > Since there is more code that passes a pointer to an uninitialized
> > variable to ufshcd_dme_get(), the untested patch below may be a better
> > solution:
> >
> > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index
> > 127b691402f9..5226fbca29ec 100644
> > --- a/drivers/ufs/core/ufshcd.c
> > +++ b/drivers/ufs/core/ufshcd.c
> > @@ -4277,8 +4277,8 @@ int ufshcd_dme_get_attr(struct ufs_hba *hba, u32
> > attr_sel,
> >    			get, UIC_GET_ATTR_ID(attr_sel),
> >    			UFS_UIC_COMMAND_RETRIES - retries);
> >
> > -	if (mib_val && !ret)
> > -		*mib_val = uic_cmd.argument3;
> > +	if (mib_val)
> > +		*mib_val = ret == 0 ? uic_cmd.argument3 : 0;
> >
> >    	if (peer && (hba->quirks & UFSHCD_QUIRK_DME_PEER_ACCESS_AUTO_MODE)
> >    	    && pwr_mode_change)
>
> There are some attributes to use 0 as valid value.
> e.g. PA_MAXRXHSGEAR is set to 0 for NO_HS=0
> If it has 0 for valid value, most of value 0 are regarded as FALSE, unsupported or minimum.
> And these cases seems to check ret for command success/fail in code.
> However, is it ok to set 0 for ufshcd_send_uic_cmd() fail?
>
> If it can't, it needs to initialize mode.
> Value 0 for PA_PWRMODE is invalid.

Hi Wonkon,

Modifying ufshcd_dme_get_attr() doesn't exclude checking the return
value of ufshcd_dme_get_attr(). I propose to modify
ufshcd_dme_get_attr() such that it always initializes *mib_val and also
to check the ufshcd_dme_get_attr() return value wherever appropriate.

Thanks,

Bart.