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 [thread overview]
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
next reply other threads:[~2019-07-29 20:50 UTC|newest]
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 ` [PATCH] driver core: platform: return -ENXIO for missing GpioInt 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
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