From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Benjamin Herrenschmidt" To: "Segher Boessenkool" Cc: Subject: Re: RFC: Performance Monitor Counters device Date: Mon, 16 Sep 2002 14:38:07 +0200 Message-Id: <20020916123807.15088@192.168.4.1> In-Reply-To: <3D831D5A.BF11BC0D@koffie.nl> References: <3D831D5A.BF11BC0D@koffie.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: >It does not exist on 7450 etc. >It exists on 7410 before version 1.3 . >I have no data on 7400. >It does not exist on 750 etc. > >[As my only G4 is a 7410 version 1.3, I won't be affected by this. Hurray.] I had it happening on 7400. >The problem itself: if two of thermal assist, decrementer, performance >monitor interrupts happen within 1 cycle of each other, evil things >happen with SRR0 and SRR1, so that the return address becomes >unrecoverable. > >Suggested solution: > >We can forget about thermal assist, as the TAU on all 74xx is broken >and unsupported. (Says those same errata sheets). >If necessary, it's possible to disable the decrementer interrupt and have >the performance monitor perform its function. > >But I won't run into this, so I'm happy for now :) We can't disable the DEC that easily as it's the primary timer source of the kernel ;) Ben. ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/