Linux-ACPI Archive on lore.kernel.org
 help / color / Atom feed
From: Brian Norris <briannorris@chromium.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	<linux-kernel@vger.kernel.org>,
	andriy.shevchenko@linux.intel.com,
	Salvatore Bellizzi <salvatore.bellizzi@linux.seppia.net>,
	andy.shevchenko@gmail.com,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	egranata@chromium.org, egranata@google.com,
	Enric Balletbo i Serra <enric.balletbo@collabora.com>,
	Gwendal Grignou <gwendal@chromium.org>,
	linux-acpi@vger.kernel.org, Benson Leung <bleung@chromium.org>,
	Brian Norris <briannorris@chromium.org>,
	stable@vger.kernel.org
Subject: [PATCH] driver core: platform: return -ENXIO for missing GpioInt
Date: Mon, 29 Jul 2019 13:49:54 -0700
Message-ID: <20190729204954.25510-1-briannorris@chromium.org> (raw)

Commit daaef255dc96 ("driver: platform: Support parsing GpioInt 0 in
platform_get_irq()") broke the Embedded Controller driver on most LPC
Chromebooks (i.e., most x86 Chromebooks), because cros_ec_lpc expects
platform_get_irq() to return -ENXIO for non-existent IRQs.
Unfortunately, acpi_dev_gpio_irq_get() doesn't follow this convention
and returns -ENOENT instead. So we get this error from cros_ec_lpc:

   couldn't retrieve IRQ number (-2)

I see a variety of drivers that treat -ENXIO specially, so rather than
fix all of them, let's fix up the API to restore its previous behavior.

I reported this on v2 of this patch:

https://lore.kernel.org/lkml/20190220180538.GA42642@google.com/

but apparently the patch had already been merged before v3 got sent out:

https://lore.kernel.org/lkml/20190221193429.161300-1-egranata@chromium.org/

and the result is that the bug landed and remains unfixed.

I differ from the v3 patch by:
 * allowing for ret==0, even though acpi_dev_gpio_irq_get() specifically
   documents (and enforces) that 0 is not a valid return value (noted on
   the v3 review)
 * adding a small comment

Reported-by: Brian Norris <briannorris@chromium.org>
Reported-by: Salvatore Bellizzi <salvatore.bellizzi@linux.seppia.net>
Cc: Enrico Granata <egranata@chromium.org>
Cc: <stable@vger.kernel.org>
Fixes: daaef255dc96 ("driver: platform: Support parsing GpioInt 0 in platform_get_irq()")
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
Side note: it might have helped alleviate some of this pain if there
were email notifications to the mailing list when a patch gets applied.
I didn't realize (and I'm not sure if Enrico did) that v2 was already
merged by the time I noted its mistakes. If I had known, I would have
suggested a follow-up patch, not a v3.

I know some maintainers' "tip bots" do this, but not all apparently.

 drivers/base/platform.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 506a0175a5a7..ec974ba9c0c4 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -157,8 +157,13 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
 	 * the device will only expose one IRQ, and this fallback
 	 * allows a common code path across either kind of resource.
 	 */
-	if (num == 0 && has_acpi_companion(&dev->dev))
-		return acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num);
+	if (num == 0 && has_acpi_companion(&dev->dev)) {
+		int ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num);
+
+		/* Our callers expect -ENXIO for missing IRQs. */
+		if (ret >= 0 || ret == -EPROBE_DEFER)
+			return ret;
+	}
 
 	return -ENXIO;
 #endif
-- 
2.22.0.709.g102302147b-goog


             reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-29 20:49 Brian Norris [this message]
2019-07-29 20:54 ` Nathan Chancellor
2019-07-29 21:03   ` Brian Norris
2019-07-29 21:09     ` Enrico Granata
2019-07-29 20:57 ` Enrico Granata
2019-07-30 11:07 ` Andy Shevchenko
2019-07-30 11:45 ` Greg Kroah-Hartman
2019-08-06 22:10 ` Brian Norris

Reply instructions:

You may reply publically 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=20190729204954.25510-1-briannorris@chromium.org \
    --to=briannorris@chromium.org \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=andy.shevchenko@gmail.com \
    --cc=bleung@chromium.org \
    --cc=dmitry.torokhov@gmail.com \
    --cc=egranata@chromium.org \
    --cc=egranata@google.com \
    --cc=enric.balletbo@collabora.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=gwendal@chromium.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rafael@kernel.org \
    --cc=salvatore.bellizzi@linux.seppia.net \
    --cc=stable@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

Linux-ACPI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-acpi/0 linux-acpi/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-acpi linux-acpi/ https://lore.kernel.org/linux-acpi \
		linux-acpi@vger.kernel.org
	public-inbox-index linux-acpi

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-acpi


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git