> -----Original Message----- > From: Life is hard, and then you die [mailto:ronald@xxxxxxxxxxxxx] > Sent: Tuesday, June 27, 2017 11:59 AM > To: Lukas Wunner <lukas@xxxxxxxxx> > Cc: Zheng, Lv <lv.zheng@xxxxxxxxx>; Rafael J. Wysocki > <rafael@xxxxxxxxxx>; Moore, Robert <robert.moore@xxxxxxxxx>; Wysocki, > Rafael J <rafael.j.wysocki@xxxxxxxxx>; ACPI Devel Maling List <linux- > acpi@xxxxxxxxxxxxxxx> > Subject: Re: ACPICA regression for empty ResourceTemplates > > > On Tue, Jun 27, 2017 at 11:24:25AM +0200, Lukas Wunner wrote: > > On Tue, Jun 27, 2017 at 01:19:31AM +0000, Zheng, Lv wrote: > > > > On Mon, Jun 26, 2017 at 01:49:03PM +0200, Rafael J. Wysocki wrote: > > > > > On Mon, Jun 26, 2017 at 10:38 AM, Lukas Wunner <lukas@xxxxxxxxx> > wrote: > > > > > > Hi Robert, > > > > > > > > > > > > ACPICA commit c8eac101 (= Linux commit a83019eb9f1f, "ACPICA: > > > > > > Update resource descriptor handling") is causing a regression > > > > > > when parsing an empty ResourceTemplate: > > > > > > Can it be fixed by using this logic: > > > if (AmlLength < sizeof (AML_RESOURCE_END_TAG) && AmlLength) Instead > > > of the logic introduced in commit a83019eb9f1f? > > > if (AmlLength < sizeof (AML_RESOURCE_END_TAG)) > > > > Unfortunately not, AmlLength is not 0 but 2 in this case (= > > sizeof(struct aml_resource_end_tag)). > > Actually, that will work here (the use of '<' ensures that). But it's > unclear whether this is semantically the correct thing, in particular > because a83019eb9f1f widened the cases where NO_RESOURCE_END_TAG is > returned, but the above suggestion narrows them. Unfortunately commit > a83019eb9f1f is quite vague about why it reverted back to '<='. > > [Moore, Robert] Yes, the <= is wrong and should be < There was an odd corner case that was solved by the <=, even though it looks stupid (and is of course incorrect for most cases.) We have not been able to reproduce this corner case again (yet), so we will revert the <= change back to the < Bob > Cheers, > > Ronald -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
