Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755597Ab0KZT3j (ORCPT ); Fri, 26 Nov 2010 14:29:39 -0500 Received: from LUNGE.MIT.EDU ([18.54.1.69]:43128 "EHLO lunge.queued.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753760Ab0KZT3i convert rfc822-to-8bit (ORCPT ); Fri, 26 Nov 2010 14:29:38 -0500 Date: Fri, 26 Nov 2010 11:29:20 -0800 From: Andres Salomon To: Daniel Drake , akpm@linux-foundation.org, linux-kernel@vger.kernel.org Cc: Thomas Gleixner Subject: Re: [PATCH v4 resend] OLPC: Add XO-1 suspend/resume support Message-ID: <20101126112920.48df6216@debxo> In-Reply-To: References: <20101118202837.B24899D401B@zog.reactivated.net> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.20.1; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2712 Lines: 83 On Fri, 26 Nov 2010 16:28:51 +0000 Daniel Drake wrote: [...] > Re. the printk thing, this was your doing: > http://dev.laptop.org/git/olpc-2.6/commit/?h=stable&id=b4334e9e1444761f19806f9066c6b38ce23079bf [...] > ---------- Forwarded message ---------- > From: Thomas Gleixner > Date: 26 November 2010 09:43 > Subject: Re: [PATCH v4 resend] OLPC: Add XO-1 suspend/resume support > To: Daniel Drake > Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org > > > On Thu, 18 Nov 2010, Daniel Drake wrote: > > Feedback after the first submission was quickly acted upon and I > > haven't been able to get a peep since. > > Sorry, fell off the radar. > > > + > > +wakeup_start: > > +# ? ?jmp wakeup_start > > ?Debug leftover ? Leftovers from the original patch; certainly should be removed. > > > +asmlinkage int olpc_xo1_do_sleep(u8 sleep_state) > > +{ > > + ? ? void *pgd_addr = __va(read_cr3()); > > + ? ? printk(KERN_ERR "xo1_do_sleep!\n"); /* this needs to remain > > here so > > + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? * that gcc doesn't > > optimize > > + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? * away our __va! */ > > + > > ?This looks suspect along with the __volatile__ magic below. Care to > ?explain, what you fear that gcc is optimizing away ? > I'm working from memory here; in the version of gcc we were using at the time (stock FC5 or FC6), setting pgd_addr immediately followed by the asm below resulted in gcc optimizing away the __va(). The asm turned into simply: movl %cr3, %eax With no mention of PAGE_OFFSET. Messing with 'volatile' didn't help. Adding the printk did, as it causes %eax to get clobbered, forcing temporary storage of %cr3 into a separate register. A lot has changed since then (compilers, this code, as well as the definition of read_cr3()), so I highly suspect that it's no longer needed. > > + ? ? /* Enable wakeup through power button */ > > + ? ? outl((CS5536_PM_PWRBTN << 16) | 0xFFFF, acpi_base + PM1_STS); > > + > > + ? ? __asm__ __volatile__("movl %0,%%eax" : : "r" (pgd_addr)); > > + ? ? __asm__("call *(%%edi); cld" > > + ? ? ? ? ? ? : : "D" (&ofw_bios_entry)); > > + ? ? __asm__ __volatile__("movb $0x34, %al\n\t" > > + ? ? ? ? ? ? ? ? ? ? ? ? ?"outb %al, $0x70\n\t" > > + ? ? ? ? ? ? ? ? ? ? ? ? ?"movb $0x30, %al\n\t" > > + ? ? ? ? ? ? ? ? ? ? ? ? ?"outb %al, $0x71\n\t"); > > Looks good otherwise. > > Thanks, > > ? ? ? ?tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/