diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-1014-Revert-mailbox-avoid-timer-start-from-callback.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-1014-Revert-mailbox-avoid-timer-start-from-callback.patch | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-1014-Revert-mailbox-avoid-timer-start-from-callback.patch b/target/linux/bcm27xx/patches-5.4/950-1014-Revert-mailbox-avoid-timer-start-from-callback.patch new file mode 100644 index 0000000000..849bdd192e --- /dev/null +++ b/target/linux/bcm27xx/patches-5.4/950-1014-Revert-mailbox-avoid-timer-start-from-callback.patch @@ -0,0 +1,60 @@ +From 2b7fcd18b15d9cc7b2e68deb77f4e0acfa904c41 Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.com> +Date: Tue, 3 Nov 2020 10:13:48 +0000 +Subject: [PATCH] Revert "mailbox: avoid timer start from callback" + +This reverts commit 6dc15642c8b830d384fd3e6c9ea63144202b8932. + +The Pi 400 shutdown/poweroff mechanism relies on being able to set +a GPIO on the expander in the pm_power_off handler, something that +requires two mailbox calls - GET_GPIO_STATE and SET_GPIO_STATE. A +recent kernel change introduces a reasonable possibility that the +GET call doesn't completes, and bisecting led to a commit from +October that changes the timer usage of the mailbox. + +My theory is that there is a race condition in the new code that breaks +the poll timer, but that it normally goes unnoticed because subsequent +mailbox activity wakes it up again. The power-off mailbox calls happen +at a time when other subsystems have been shut down, so if one of them +fails then there is nothing to allow it to recover. + +Revert 6dc15642 as (at least) a workaround. + +See: https://github.com/raspberrypi/linux/issues/3941 + +Signed-off-by: Phil Elwell <phil@raspberrypi.com> +--- + drivers/mailbox/mailbox.c | 12 +++++------- + 1 file changed, 5 insertions(+), 7 deletions(-) + +--- a/drivers/mailbox/mailbox.c ++++ b/drivers/mailbox/mailbox.c +@@ -82,12 +82,9 @@ static void msg_submit(struct mbox_chan + exit: + spin_unlock_irqrestore(&chan->lock, flags); + +- /* kick start the timer immediately to avoid delays */ +- if (!err && (chan->txdone_method & TXDONE_BY_POLL)) { +- /* but only if not already active */ +- if (!hrtimer_active(&chan->mbox->poll_hrt)) +- hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); +- } ++ if (!err && (chan->txdone_method & TXDONE_BY_POLL)) ++ /* kick start the timer immediately to avoid delays */ ++ hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); + } + + static void tx_tick(struct mbox_chan *chan, int r) +@@ -125,10 +122,11 @@ static enum hrtimer_restart txdone_hrtim + struct mbox_chan *chan = &mbox->chans[i]; + + if (chan->active_req && chan->cl) { +- resched = true; + txdone = chan->mbox->ops->last_tx_done(chan); + if (txdone) + tx_tick(chan, 0); ++ else ++ resched = true; + } + } + |