59 lines
2.1 KiB
Diff
59 lines
2.1 KiB
Diff
From a8fb0d43b8acd25d68a0d2c24fd0260393148447 Mon Sep 17 00:00:00 2001
|
|
From: Phil Elwell <phil@raspberrypi.com>
|
|
Date: Tue, 3 Nov 2020 11:49:53 +0000
|
|
Subject: [PATCH] Revert "mailbox: avoid timer start from callback"
|
|
|
|
This reverts commit c7dacf5b0f32957b24ef29df1207dc2cd8307743.
|
|
|
|
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.
|
|
|
|
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;
|
|
}
|
|
}
|
|
|