| Message ID | 1475614300-133004-1-git-send-email-srinivas.pandruvada@linux.intel.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Tuesday, October 04, 2016 01:51:40 PM Srinivas Pandruvada wrote: > On some platforms with ACPI4 variable speed fan, reading cur_state from > cooling device returns "invalid value" error. This confuses user space > applications. > > This issue occurs as the current driver doesn't take account of > "FineGrainControl" from _FIF(Fan Information). When the "FineGrainControl" > is set, _FSL(FSL Set Level) takes argument as a percent, which doesn't > have to match from any control value from _FPS(Fan Performance States). > It is also possible that the Fan is not actually running at the requested > speed returning a lower speed. > On some platforms the BIOS is setting fan speed to a level during boot, > which will not have an exact match to _FPS control values. The current > implementation will treat this level as invalid value. > > The simple change is to atleast return state corresponding to a maximum > control value in the _FPS compared to the current level. > > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > --- > drivers/acpi/fan.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/acpi/fan.c b/drivers/acpi/fan.c > index 384cfc3..f34859a 100644 > --- a/drivers/acpi/fan.c > +++ b/drivers/acpi/fan.c > @@ -129,8 +129,18 @@ static int fan_get_state_acpi4(struct acpi_device *device, unsigned long *state) > > control = obj->package.elements[1].integer.value; > for (i = 0; i < fan->fps_count; i++) { > - if (control == fan->fps[i].control) > + /* > + * When Fine grain control is set, return the state > + * corresponding to maximum fan->fps[i].control > + * value compared to the current speed. Here the > + * fan->fps[] is sorted array with increasing speed. > + */ > + if (fan->fif.fine_grain_ctrl && control < fan->fps[i].control) { > + i = (i > 0) ? i - 1 : 0; > break; > + } else if (control == fan->fps[i].control) { > + break; > + } > } > if (i == fan->fps_count) { > dev_dbg(&device->dev, "Invalid control value returned\n"); > Applied. Thanks, Rafael -- 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
diff --git a/drivers/acpi/fan.c b/drivers/acpi/fan.c index 384cfc3..f34859a 100644 --- a/drivers/acpi/fan.c +++ b/drivers/acpi/fan.c @@ -129,8 +129,18 @@ static int fan_get_state_acpi4(struct acpi_device *device, unsigned long *state) control = obj->package.elements[1].integer.value; for (i = 0; i < fan->fps_count; i++) { - if (control == fan->fps[i].control) + /* + * When Fine grain control is set, return the state + * corresponding to maximum fan->fps[i].control + * value compared to the current speed. Here the + * fan->fps[] is sorted array with increasing speed. + */ + if (fan->fif.fine_grain_ctrl && control < fan->fps[i].control) { + i = (i > 0) ? i - 1 : 0; break; + } else if (control == fan->fps[i].control) { + break; + } } if (i == fan->fps_count) { dev_dbg(&device->dev, "Invalid control value returned\n");
On some platforms with ACPI4 variable speed fan, reading cur_state from cooling device returns "invalid value" error. This confuses user space applications. This issue occurs as the current driver doesn't take account of "FineGrainControl" from _FIF(Fan Information). When the "FineGrainControl" is set, _FSL(FSL Set Level) takes argument as a percent, which doesn't have to match from any control value from _FPS(Fan Performance States). It is also possible that the Fan is not actually running at the requested speed returning a lower speed. On some platforms the BIOS is setting fan speed to a level during boot, which will not have an exact match to _FPS control values. The current implementation will treat this level as invalid value. The simple change is to atleast return state corresponding to a maximum control value in the _FPS compared to the current level. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> --- drivers/acpi/fan.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)