Thread (22 messages) 22 messages, 7 authors, 2012-09-26

Re: [RFT/PATCH] serial: omap: prevent resume if device is not suspended.

From: Felipe Balbi <hidden>
Date: 2012-09-18 14:07:07
Also in: linux-arm-kernel, linux-omap, lkml

On Tue, Sep 18, 2012 at 06:10:50PM +0530, Sourav Poddar wrote:
Greg's tty-next is not booting on 2420 based N800. The failure is
observed at serial init itself. The reason might be that n800 tries to
resume even though it is not suspended before.

Reported-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Sourav Poddar <redacted>
FWIW:

Reviewed-by: Felipe Balbi <redacted>

Paul does this fix the issue for you ? Note that it depends on a
previous patch Sourav sent [1]

[1] http://marc.info/?l=linux-omap&m=134796819607889&w=2

There's one thing that gets my attention, though, why only n800 would
fail here ?

I wonder if we should be using:

pm_runtime_set_active(dev);
pm_runtime_get_enable(dev);

to prevent our runtime_resume() to be called from probe, but Sourav
tested and it doesn't work on BeagleBoard, but it works on PandaBoard.

Does it ring any bell ??
quoted hunk ↗ jump to hunk
---
This patch is developed on top of greg's tty-next branch
CommitId: e740d8f tty: serial: Samsung: Fix return value +
the following patch which I have already posted to the mailing list.
http://comments.gmane.org/gmane.linux.ports.arm.omap/84729

 drivers/tty/serial/omap-serial.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 3c05c5e..bc355f2 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -110,6 +110,7 @@ struct uart_omap_port {
 	u32			calc_latency;
 	struct work_struct	qos_work;
 	struct pinctrl		*pins;
+	unsigned int		suspended:1;
 };
 
 #define to_uart_omap_port(p)	((container_of((p), struct uart_omap_port, port)))
@@ -1545,14 +1546,20 @@ static int serial_omap_runtime_suspend(struct device *dev)
 	up->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
 	schedule_work(&up->qos_work);
 
+	up->suspended = true;
+
 	return 0;
 }
 
 static int serial_omap_runtime_resume(struct device *dev)
 {
 	struct uart_omap_port *up = dev_get_drvdata(dev);
+	u32 loss_cnt;
+
+	if (!up->suspended)
+		return 0;
 
-	u32 loss_cnt = serial_omap_get_context_loss_count(up);
+	loss_cnt = serial_omap_get_context_loss_count(up);
 
 	if (up->context_loss_cnt != loss_cnt)
 		serial_omap_restore_context(up);
@@ -1560,6 +1567,8 @@ static int serial_omap_runtime_resume(struct device *dev)
 	up->latency = up->calc_latency;
 	schedule_work(&up->qos_work);
 
+	up->suspended = false;
+
 	return 0;
 }
 #endif
-- 
1.7.1
-- 
balbi

Attachments

Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help