LKML Archive on lore.kernel.org help / color / mirror / Atom feed
From: Ondrej Zary <email@example.com> To: Bjorn Helgaas <firstname.lastname@example.org> Cc: Jaroslav Kysela <email@example.com>, Rene Herman <firstname.lastname@example.org>, Andrew Morton <email@example.com>, "Rafael J. Wysocki" <firstname.lastname@example.org>, Pierre Ossman <email@example.com>, Pavel Machek <firstname.lastname@example.org>, ALSA development <email@example.com>, Linux Kernel <firstname.lastname@example.org>, Takashi Iwai <email@example.com>, firstname.lastname@example.org Subject: Re: -mm: pnp-do-not-stop-start-devices-in-suspend-resume-path.patch breaks resuming isapnp cards Date: Wed, 16 Jan 2008 19:03:23 +0100 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <firstname.lastname@example.org> On Wednesday 16 January 2008 18:46:03 Bjorn Helgaas wrote: > On Tuesday 15 January 2008 12:51:35 am Jaroslav Kysela wrote: > > On Mon, 14 Jan 2008, Bjorn Helgaas wrote: > > > On Saturday 12 January 2008 11:13:35 pm Rene Herman wrote: > > > > ... And, now that I have your attention, while it's > > > > not important to the issue anymore with the tests removed as the > > > > submitted patch did, do you have an opinion on (include/linux/pnp.h): > > > > > > > > /* pnp driver flags */ > > > > #define PNP_DRIVER_RES_DO_NOT_CHANGE 0x0001 /* do not change the > > > > state of the device */ > > > > #define PNP_DRIVER_RES_DISABLE 0x0003 /* ensure the device > > > > is disabled */ > > > > > > > > I find DISABLE including DO_NOT_CHANGE rather unexpected... > > > > > > I don't know the history of those flags, but I wish they didn't exist. > > > > Ok, something to explain. These flags exists to allow drivers to > > manually configure (override) PnP resources at init time - we know - for > > example in ALSA - that some combinations simply does not work for all > > soundcards. > > > > The DISABLE flags simply tells core PnP layer - driver will handle > > resource allocation itself, don't do anything, just disable hw physically > > and do not change (allocate) any resources. Value 0x03 is valid in this > > semantics. > > It looks like sound drivers use PNP_DRIVER_RES_DISABLE to say "ignore > what PNP tells us about resource usage and we'll just use the compiled- > in or command-line-specified resources". > > The main reason to do that would be to work around BIOS defects or > to work around deficiencies in the Linux PNP infrastructure (e.g., > maybe we erroneously place another device on top of the sound card > or something). > > I'm just suspicious because PNP_DRIVER_RES_DISABLE is only used in > sound drivers. If it's to work around BIOS defects, why wouldn't > other PNP drivers need it sometimes, too? And wouldn't it be better > to use PNP quirks for BIOS workarounds? > > > Unfortunately, suspend / resume complicates things a bit, but PnP core > > can handle DO_NOT_CHANGE flag. But it will just mean - _preserve_ > > resource allocation from last suspend state for this device and enable hw > > physically before calling resume() callback. > > When resuming, wouldn't we *always* want to preserve the resource > allocation from the last suspend, regardless of whether > PNP_DRIVER_RES_DO_NOT_CHANGE is specified? I'd say yes. If base address of a card changes, driver will break. I grepped drivers for these flags too - to find out what they do (or should do?) - but failed to find out anything useful. > Linux PNP definitely has issues with suspend/resume, and I suspect > this is one of them. > > Bjorn > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to email@example.com > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Ondrej Zary
next prev parent reply other threads:[~2008-01-16 18:33 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2008-01-09 22:43 PNP_DRIVER_RES_DISABLE breaks swsusp at least with snd_cs4236 Ondrej Zary 2008-01-10 1:53 ` [alsa-devel] " Rene Herman 2008-01-10 7:58 ` Jaroslav Kysela 2008-01-11 1:19 ` Rene Herman 2008-01-11 7:01 ` Pierre Ossman 2008-01-11 14:21 ` Rene Herman 2008-01-11 18:40 ` Ondrej Zary 2008-01-12 1:23 ` Rene Herman 2008-01-12 11:12 ` Pierre Ossman 2008-01-12 13:39 ` Rene Herman 2008-01-12 15:21 ` Pierre Ossman 2008-01-12 16:46 ` Ondrej Zary 2008-01-12 17:00 ` Rene Herman 2008-01-12 19:08 ` Rafael J. Wysocki 2008-01-12 20:08 ` -mm: pnp-do-not-stop-start-devices-in-suspend-resume-path.patch breaks resuming isapnp cards Rene Herman 2008-01-13 5:50 ` Bjorn Helgaas 2008-01-13 6:13 ` Rene Herman 2008-01-14 22:26 ` Bjorn Helgaas 2008-01-14 23:46 ` Rene Herman 2008-01-15 7:51 ` Jaroslav Kysela 2008-01-16 17:46 ` Bjorn Helgaas 2008-01-16 18:03 ` Ondrej Zary [this message] 2008-01-16 18:16 ` Rene Herman 2008-01-12 19:01 ` [alsa-devel] PNP_DRIVER_RES_DISABLE breaks swsusp at least with snd_cs4236 Rafael J. Wysocki
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).