Date: Fri, 27 Jan 2012 21:49:02 +0000 (UTC) From: Warner Losh <imp@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r230626 - head/sys/dev/pccbb Message-ID: <201201272149.q0RLn2U3061917@svn.freebsd.org>
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Author: imp Date: Fri Jan 27 21:49:02 2012 New Revision: 230626 URL: http://svn.freebsd.org/changeset/base/230626 Log: Some laptops have weak power controllers that cannot tolerate multiple cards powering up at once. Work around the easy case (multiple cards inserted on boot) with a short sleep and a long comment. This improves reliability on those laptops with power hungry cards. Modified: head/sys/dev/pccbb/pccbb.c Modified: head/sys/dev/pccbb/pccbb.c ============================================================================== --- head/sys/dev/pccbb/pccbb.c Fri Jan 27 21:22:07 2012 (r230625) +++ head/sys/dev/pccbb/pccbb.c Fri Jan 27 21:49:02 2012 (r230626) @@ -460,6 +460,13 @@ cbb_event_thread(void *arg) int err; int not_a_card = 0; + /* + * We need to act as a power sequencer on startup. Delay 2s/channel + * to ensure the other channels have had a chance to come up. We likely + * should add a lock that's shared on a per-slot basis so that only + * one power event can happen per slot at a time. + */ + pause("cbbstart", hz * device_get_unit(sc->dev) * 2); mtx_lock(&sc->mtx); sc->flags |= CBB_KTHREAD_RUNNING; while ((sc->flags & CBB_KTHREAD_DONE) == 0) {
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