From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: Re: uhci-hcd suspend/resume under the new driver model Date: Mon, 14 Mar 2005 10:59:25 -0800 Message-ID: <200503141059.26107.david-b@pacbell.net> References: <20050313101453.GA4820@blackham.com.au> <200503141017.17305.david-b@pacbell.net> <20050314184454.GL5461@elf.ucw.cz> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============54162464463900095==" In-Reply-To: <20050314184454.GL5461-I/5MKhXcvmPrBKCeMvbIDA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces-qjLDD68F18O7TbgM5vRIOg@public.gmane.org Errors-To: linux-pm-bounces-qjLDD68F18O7TbgM5vRIOg@public.gmane.org To: Pavel Machek Cc: Bernard Blackham , ncunningham-3EexvZdKGZRWk0Htik3J/w@public.gmane.org, linux-pm-qjLDD68F18O7TbgM5vRIOg@public.gmane.org List-Id: linux-pm@vger.kernel.org --===============54162464463900095== Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Monday 14 March 2005 10:44 am, Pavel Machek wrote: > Hi! > > > > I'll really need to make pci_choose_state > > > "NOP" in the current code, so that it can be safely added to the > > > existing drivers. > > > > There's no point in adding NOPs. Why bother? > > > > Remember, the original idea behind pci_choose_state() was that > > PCI drivers for PM-aware devices could use that instead of their > > own dumb mappings between system suspend states (S0, S1, S2, S3, > > S4, etc) and PCI states ... which in too many cases was just to > > re-use the same numeric value. That's _never_ going to be a NOP, > > unless Linux only ever supports PCI D3hot (ACPI D2) and S3; and > > likewise will never be needed for PM-stupid devices, or for those > > drivers with actual intelligence (e.g. Ben's video examples). > > When I added pci_choose_state to drivers, I commented it as "no code > changes". I was wrong. That's sort of what I said. If it's a NOP, why bother? The idea behind such an API was to support S1/S2/S3 suspend levels, where D3hot may be sub-optimal. That's not NOP-ville. And it probably ought to consult ACPI tables on some systems... > pci_choose_state() needs to return d3hot even > for pmsg_freeze, because that's what old code did, and I did not audit > all the drivers. Seems like a problem to me. Do S1/S2/S3 transitions even need a "freeze" transition? I thought we'd agreed they don't; that such transitions were needed only under swsusp models, ensuring the image written to swap was internally consistent. (Non-swsusp models only have the memory image, which will by definition be internally consistent.) > > My original question is unanswered though: what tree is it that > > made these (broken) changes to USB? It's not BK-current, and it's > > not the USB tree... > > suspend2 tree and my personal tree. OK, so nothing for me to worry about unless someone tries pushing those changes upstream. - Dave --===============54162464463900095== Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline --===============54162464463900095==--