From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-serial@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, Johan Hovold <jhovold@gmail.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH] tty: serial: pch: don't crash if DMA enabled but not loaded
Date: Wed, 4 Dec 2013 20:52:49 +0100 [thread overview]
Message-ID: <1386186769-12708-1-git-send-email-bigeasy@linutronix.de> (raw)
if the DMA driver isn't loaded "on time" then we crash in the irq handler:
| pch_uart 0000:02:0a.4: pch_request_dma:dma_request_channel FAILS(Tx)
| BUG: unable to handle kernel NULL pointer dereference at (null)
| IP: [<c0676ed9>] pch_uart_interrupt+0x739/0x940
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/tty/serial/pch_uart.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 20e4c94..9b7cd40 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1492,10 +1492,14 @@ static int pch_uart_verify_port(struct uart_port *port,
__func__);
return -EOPNOTSUPP;
#endif
- dev_info(priv->port.dev, "PCH UART : Use DMA Mode\n");
- if (!priv->use_dma)
+ if (!priv->use_dma) {
pch_request_dma(port);
- priv->use_dma = 1;
+ if (priv->chan_rx)
+ priv->use_dma = 1;
+ }
+ dev_info(priv->port.dev, "PCH UART: %s\n",
+ priv->use_dma ?
+ "Use DMA Mode" : "No DMA");
}
return 0;
--
1.8.4.4
reply other threads:[~2013-12-04 19:52 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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 \
--in-reply-to=1386186769-12708-1-git-send-email-bigeasy@linutronix.de \
--to=bigeasy@linutronix.de \
--cc=gregkh@linuxfoundation.org \
--cc=jhovold@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.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: link
Be 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).