From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhang Rui Subject: Re: [PATCH] ACPI / scan: Allow ACPI drivers to bind to PNP device objects Date: Sun, 24 Aug 2014 15:06:50 +0800 Message-ID: <1408864010.3315.47.camel@rzhang1-toshiba> References: <5487060.QsgluucUH4@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5487060.QsgluucUH4@vostro.rjw.lan> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: ACPI Devel Maling List , Linux Kernel Mailing List , Gabriele Mazzotta , Dirk Griesbach , Matthew Garrett List-Id: linux-acpi@vger.kernel.org On Thu, 2014-08-21 at 06:04 +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > 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-and-tested-by: Gabriele Mazzotta > Reported-and-tested-by: Dirk Griesbach > Signed-off-by: Rafael J. Wysocki > --- > drivers/acpi/acpi_pnp.c | 5 +++++ > drivers/acpi/internal.h | 1 + > drivers/acpi/scan.c | 2 +- > 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. thanks, rui > Index: linux-pm/drivers/acpi/internal.h > =================================================================== > --- linux-pm.orig/drivers/acpi/internal.h > +++ linux-pm/drivers/acpi/internal.h > @@ -86,6 +86,7 @@ void acpi_device_add_finalize(struct acp > void acpi_free_pnp_ids(struct acpi_device_pnp *pnp); > bool acpi_device_is_present(struct acpi_device *adev); > bool acpi_device_is_battery(struct acpi_device *adev); > +bool is_acpi_pnp_device(struct acpi_device *adev); > > /* -------------------------------------------------------------------------- > Power Resource > 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 && !is_acpi_pnp_device(acpi_dev)) > return -EINVAL; > > if (!acpi_drv->ops.add)