Re: [patch] USB after second suspend/resume on ThinkPads.

On Wednesday, June 18, 2014 2:46:09 pm Edward Tomasz Napierała wrote:
> On 0618T1303, John Baldwin wrote:
> > On Wednesday, June 18, 2014 12:13:15 pm Edward Tomasz Napierała wrote:
> > > On 0618T0947, John Baldwin wrote:
> > > > On Monday, June 16, 2014 3:21:55 pm Edward Tomasz Napierała wrote:
> > > > > Hi.  Patch below should fix a problem where USB stops working after
> > > > > _second_ suspend/resume, which happens on various ThinkPad models.
> > > > > Please test, and report both success stories and failures.  If nothing
> > > > > comes up, I'll commit it in a week or so.
> > > > 
> > > > Good find.  Have you thought about a more generic fix for this wherein you 
> > > > track power resources and flip them on during resume in ACPI before doing
> > > > DEVICE_RESUME() on the root bus?
> > > 
> > > Thing is, after resume this device claims to be on already.  The following
> > > simple hack was enough to make it work:
> > 
> > Ahh, I think I see.  Try this instead:
> > 
> > Index: sys/dev/acpica/acpi_powerres.c
> > ===================================================================
> > --- acpi_powerres.c	(revision 267550)
> > +++ acpi_powerres.c	(working copy)
> > _at__at_ -645,7 +645,7 _at__at_ acpi_pwr_switch_power(void)
> >  			      acpi_name(rp->ap_resource), status));
> >  	    /* XXX is this correct?  Always switch if in doubt? */
> >  	    continue;
> > -	} else if (rp->ap_state == ACPI_PWR_UNK)
> > +	} else
> >  	    rp->ap_state = cur;
> >  
> >  	/*
> > _at__at_ -689,7 +689,7 _at__at_ acpi_pwr_switch_power(void)
> >  			      acpi_name(rp->ap_resource), status));
> >  	    /* XXX is this correct?  Always switch if in doubt? */
> >  	    continue;
> > -	} else if (rp->ap_state == ACPI_PWR_UNK)
> > +	} else
> >  	    rp->ap_state = cur;
> >  
> >  	/*
> > 
> > (We were ignoring what _STA told us and believed it was ON because we had
> >  cached that state previously.)
> 
> Works!

Hmmm.  If we go this route, ap_state is actually useless and should just be
removed.  Here is an updated version that does that.  If this works as well
then this is probably a commit candidate.

Index: acpi_powerres.c
===================================================================
--- acpi_powerres.c	(revision 267550)
+++ acpi_powerres.c	(working copy)
_at__at_ -64,7 +64,6 _at__at_ ACPI_MODULE_NAME("POWERRES")
 /* Return values from _STA on a power resource */
 #define ACPI_PWR_OFF	0
 #define ACPI_PWR_ON	1
-#define ACPI_PWR_UNK	(-1)
 
 /* A relationship between a power resource and a consumer. */
 struct acpi_powerreference {
_at__at_ -90,7 +89,6 _at__at_ struct acpi_powerresource {
     ACPI_HANDLE				ap_resource;
     UINT64				ap_systemlevel;
     UINT64				ap_order;
-    int					ap_state;
 };
 
 static TAILQ_HEAD(acpi_powerresource_list, acpi_powerresource)
_at__at_ -173,7 +171,6 _at__at_ acpi_pwr_register_resource(ACPI_HANDLE res)
     }
     rp->ap_systemlevel = obj->PowerResource.SystemLevel;
     rp->ap_order = obj->PowerResource.ResourceOrder;
-    rp->ap_state = ACPI_PWR_UNK;
     
     /* Sort the resource into the list */
     status = AE_OK;
_at__at_ -638,7 +635,6 _at__at_ acpi_pwr_switch_power(void)
 	    continue;
 	}
 
-	/* We could cache this if we trusted it not to change under us */
 	status = acpi_GetInteger(rp->ap_resource, "_STA", &cur);
 	if (ACPI_FAILURE(status)) {
 	    ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get status of %s - %d\n",
_at__at_ -645,8 +641,7 _at__at_ acpi_pwr_switch_power(void)
 			      acpi_name(rp->ap_resource), status));
 	    /* XXX is this correct?  Always switch if in doubt? */
 	    continue;
-	} else if (rp->ap_state == ACPI_PWR_UNK)
-	    rp->ap_state = cur;
+	}
 
 	/*
 	 * Switch if required.  Note that we ignore the result of the switch
_at__at_ -653,7 +648,7 _at__at_ acpi_pwr_switch_power(void)
 	 * effort; we don't know what to do if it fails, so checking wouldn't
 	 * help much.
 	 */
-	if (rp->ap_state != ACPI_PWR_ON) {
+	if (cur != ACPI_PWR_ON) {
 	    status = AcpiEvaluateObject(rp->ap_resource, "_ON", NULL, NULL);
 	    if (ACPI_FAILURE(status)) {
 		ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
_at__at_ -661,7 +656,6 _at__at_ acpi_pwr_switch_power(void)
 				 acpi_name(rp->ap_resource),
 				 AcpiFormatException(status)));
 	    } else {
-		rp->ap_state = ACPI_PWR_ON;
 		ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "switched %s on\n",
 				 acpi_name(rp->ap_resource)));
 	    }
_at__at_ -682,7 +676,6 _at__at_ acpi_pwr_switch_power(void)
 	    continue;
 	}
 
-	/* We could cache this if we trusted it not to change under us */
 	status = acpi_GetInteger(rp->ap_resource, "_STA", &cur);
 	if (ACPI_FAILURE(status)) {
 	    ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get status of %s - %d\n",
_at__at_ -689,8 +682,7 _at__at_ acpi_pwr_switch_power(void)
 			      acpi_name(rp->ap_resource), status));
 	    /* XXX is this correct?  Always switch if in doubt? */
 	    continue;
-	} else if (rp->ap_state == ACPI_PWR_UNK)
-	    rp->ap_state = cur;
+	}
 
 	/*
 	 * Switch if required.  Note that we ignore the result of the switch
_at__at_ -697,7 +689,7 _at__at_ acpi_pwr_switch_power(void)
 	 * effort; we don't know what to do if it fails, so checking wouldn't
 	 * help much.
 	 */
-	if (rp->ap_state != ACPI_PWR_OFF) {
+	if (cur != ACPI_PWR_OFF) {
 	    status = AcpiEvaluateObject(rp->ap_resource, "_OFF", NULL, NULL);
 	    if (ACPI_FAILURE(status)) {
 		ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
_at__at_ -705,7 +697,6 _at__at_ acpi_pwr_switch_power(void)
 				 acpi_name(rp->ap_resource),
 				 AcpiFormatException(status)));
 	    } else {
-		rp->ap_state = ACPI_PWR_OFF;
 		ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "switched %s off\n",
 				 acpi_name(rp->ap_resource)));
 	    }


-- 
John Baldwin