From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] ACPI / scan: Allow ACPI drivers to bind to PNP device objects Date: Tue, 26 Aug 2014 00:25:09 +0200 Message-ID: <1493252.guStSdlKdN@vostro.rjw.lan> References: <5487060.QsgluucUH4@vostro.rjw.lan> <1408864010.3315.47.camel@rzhang1-toshiba> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <1408864010.3315.47.camel@rzhang1-toshiba> Sender: linux-kernel-owner@vger.kernel.org To: Zhang Rui Cc: ACPI Devel Maling List , Linux Kernel Mailing List , Gabriele Mazzotta , Dirk Griesbach , Matthew Garrett List-Id: linux-acpi@vger.kernel.org On Sunday, August 24, 2014 03:06:50 PM Zhang Rui wrote: > On Thu, 2014-08-21 at 06:04 +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki [cut] > > 3 files changed, 7 insertions(+), 1 deletion(-) > > > > Index: linux-pm/drivers/acpi/acpi_pnp.c > > =================================================================== > > --- linux-pm.orig/drivers/acpi/acpi_pnp.c > > +++ linux-pm/drivers/acpi/acpi_pnp.c > > @@ -396,3 +396,8 @@ void __init acpi_pnp_init(void) > > { > > acpi_scan_add_handler(&acpi_pnp_handler); > > } > > + > > +bool is_acpi_pnp_device(struct acpi_device *adev) > > +{ > > + return adev->handler == &acpi_pnp_handler; > > +} > > can we reuse acpi_is_pnp_device()? > The only difference is that acpi_is_pnp_device() returns true for > RTC_CMOS devices, which is not a problem IMO because RTC CMOS devices > have PNP driver only. Yes, we can. Overlooked that. Updated patch is appended. Rafael --- From: Rafael J. Wysocki Subject: [PATCH] ACPI / scan: Allow ACPI drivers to bind to PNP device objects We generally don't allow ACPI drivers to bind to ACPI device objects that companion "physical" device objects are created for to avoid situations in which two different drivers may attempt to handle one device at the same time. Recent ACPI device enumeration rework extended that approach to ACPI PNP devices by starting to use a scan handler for enumerating them. However, we previously allowed ACPI drivers to bind to ACPI device objects with existing PNP device companions and changing that led to functional regressions on some systems. For this reason, add a special check for PNP devices in acpi_device_probe() so that ACPI drivers can bind to ACPI device objects having existing PNP device companions as before. Fixes: eec15edbb0e1 (ACPI / PNP: use device ID list for PNPACPI device enumeration) Link: https://bugzilla.kernel.org/show_bug.cgi?id=81511 Link: https://bugzilla.kernel.org/show_bug.cgi?id=81971 Reported-by: Gabriele Mazzotta Reported-by: Dirk Griesbach Signed-off-by: Rafael J. Wysocki --- drivers/acpi/scan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-pm/drivers/acpi/scan.c =================================================================== --- linux-pm.orig/drivers/acpi/scan.c +++ linux-pm/drivers/acpi/scan.c @@ -975,7 +975,7 @@ static int acpi_device_probe(struct devi struct acpi_driver *acpi_drv = to_acpi_driver(dev->driver); int ret; - if (acpi_dev->handler) + if (acpi_dev->handler && !acpi_is_pnp_device(acpi_dev)) return -EINVAL; if (!acpi_drv->ops.add)