| Message ID | 20090127130455.2c1b0cd4.akpm@linux-foundation.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
-- Len Brown, Intel Open Source Technology Center On Tue, 27 Jan 2009, Andrew Morton wrote: > On Tue, 20 Jan 2009 12:18:24 +0100 > Holger Macht <hmacht@suse.de> wrote: > > > Cc: stable@kernel.org > > The patch applied OK to 2.6.28 but not to any earlier kernel. If we > decide that it should be backported to 2.6.27 or earlier, a new patch > might be needed for that. > > > Some devices trigger a DEVICE_CHECK on every evalutation of _STA. This > > can also be seen in commit 8b59560a3baf2e7c24e0fb92ea5d09eca92805db > > (ACPI: dock: avoid check _STA method). If an undock is processed, the > > dock driver sends a uevent and userspace might read the show_docked > > property in sysfs. This causes an evaluation of _STA of the particular > > device which causes the dock driver to immediately dock again. > > > > In any case, evaluation of _STA (show_docked) does not necessarily mean > > that we are docked, so check with the internal device structure. > > > > http://bugzilla.kernel.org/show_bug.cgi?id=12360 > > > > Signed-off-by: Holger Macht <hmacht@suse.de> > > --- > > > > diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c > > index 5b30b8d..afd5db3 100644 > > --- a/drivers/acpi/dock.c > > +++ b/drivers/acpi/dock.c > > @@ -855,10 +855,14 @@ fdd_out: > > static ssize_t show_docked(struct device *dev, > > struct device_attribute *attr, char *buf) > > { > > + struct acpi_device *tmp; > > + > > struct dock_station *dock_station = *((struct dock_station **) > > dev->platform_data); > > - return snprintf(buf, PAGE_SIZE, "%d\n", dock_present(dock_station)); > > > > + if (ACPI_SUCCESS(acpi_bus_get_device(dock_station->handle, &tmp))) > > + return snprintf(buf, PAGE_SIZE, "1\n"); > > + return snprintf(buf, PAGE_SIZE, "0\n"); > > } > > static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL); > > That seems a little overwrought. Won't plain old strcpy suffice? > > > --- a/drivers/acpi/dock.c~acpi-dock-dont-eval-_sta-on-every-show_docked-sysfs-read-simplification > +++ a/drivers/acpi/dock.c > @@ -861,8 +861,8 @@ static ssize_t show_docked(struct device > dev->platform_data); > > if (ACPI_SUCCESS(acpi_bus_get_device(dock_station->handle, &tmp))) > - return snprintf(buf, PAGE_SIZE, "1\n"); > - return snprintf(buf, PAGE_SIZE, "0\n"); > + return strcpy(buf, "1\n"); > + return strcpy(buf, "0\n"); > } > static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL); > > _ > sure, strcpy is fine b/c the src and dest are known to not be in danger of overlow. applied to acpi misc branch. thanks, -Len -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 06 Feb 2009 22:11:15 -0500 (EST) Len Brown <lenb@kernel.org> wrote: > > > -- > Len Brown, Intel Open Source Technology Center > > On Tue, 27 Jan 2009, Andrew Morton wrote: > > > On Tue, 20 Jan 2009 12:18:24 +0100 > > Holger Macht <hmacht@suse.de> wrote: > > > > > Cc: stable@kernel.org > > > > The patch applied OK to 2.6.28 but not to any earlier kernel. If we > > decide that it should be backported to 2.6.27 or earlier, a new patch > > might be needed for that. > > > > > Some devices trigger a DEVICE_CHECK on every evalutation of _STA. This > > > can also be seen in commit 8b59560a3baf2e7c24e0fb92ea5d09eca92805db > > > (ACPI: dock: avoid check _STA method). If an undock is processed, the > > > dock driver sends a uevent and userspace might read the show_docked > > > property in sysfs. This causes an evaluation of _STA of the particular > > > device which causes the dock driver to immediately dock again. > > > > > > In any case, evaluation of _STA (show_docked) does not necessarily mean > > > that we are docked, so check with the internal device structure. > > > > > > http://bugzilla.kernel.org/show_bug.cgi?id=12360 > > > > > > Signed-off-by: Holger Macht <hmacht@suse.de> > > > --- > > > > > > diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c > > > index 5b30b8d..afd5db3 100644 > > > --- a/drivers/acpi/dock.c > > > +++ b/drivers/acpi/dock.c > > > @@ -855,10 +855,14 @@ fdd_out: > > > static ssize_t show_docked(struct device *dev, > > > struct device_attribute *attr, char *buf) > > > { > > > + struct acpi_device *tmp; > > > + > > > struct dock_station *dock_station = *((struct dock_station **) > > > dev->platform_data); > > > - return snprintf(buf, PAGE_SIZE, "%d\n", dock_present(dock_station)); > > > > > > + if (ACPI_SUCCESS(acpi_bus_get_device(dock_station->handle, &tmp))) > > > + return snprintf(buf, PAGE_SIZE, "1\n"); > > > + return snprintf(buf, PAGE_SIZE, "0\n"); > > > } > > > static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL); > > > > That seems a little overwrought. Won't plain old strcpy suffice? > > > > > > --- a/drivers/acpi/dock.c~acpi-dock-dont-eval-_sta-on-every-show_docked-sysfs-read-simplification > > +++ a/drivers/acpi/dock.c > > @@ -861,8 +861,8 @@ static ssize_t show_docked(struct device > > dev->platform_data); > > > > if (ACPI_SUCCESS(acpi_bus_get_device(dock_station->handle, &tmp))) > > - return snprintf(buf, PAGE_SIZE, "1\n"); > > - return snprintf(buf, PAGE_SIZE, "0\n"); > > + return strcpy(buf, "1\n"); > > + return strcpy(buf, "0\n"); > > } > > static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL); > > > > _ > > > > sure, strcpy is fine b/c the src and dest are known to not be in danger of > overlow. applied to acpi misc branch. argh, sorry, don't apply the strcpy() version - it's buggy. It returns the address of the string (and a compile warning) rather than the amount-of-data-available. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- a/drivers/acpi/dock.c~acpi-dock-dont-eval-_sta-on-every-show_docked-sysfs-read-simplification +++ a/drivers/acpi/dock.c @@ -861,8 +861,8 @@ static ssize_t show_docked(struct device dev->platform_data); if (ACPI_SUCCESS(acpi_bus_get_device(dock_station->handle, &tmp))) - return snprintf(buf, PAGE_SIZE, "1\n"); - return snprintf(buf, PAGE_SIZE, "0\n"); + return strcpy(buf, "1\n"); + return strcpy(buf, "0\n"); } static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL);