Hi, > From: Rafael J. Wysocki [mailto:rjw@xxxxxxxxxxxxx] > Sent: Monday, November 24, 2014 11:20 PM > Lv > Subject: Re: [PATCH v3 updated 3/3] ACPI / PMIC: AXP288: support virtual GPIO in ACPI table > > On Monday, November 24, 2014 05:32:33 PM Aaron Lu wrote: > > On 11/24/2014 09:06 AM, Rafael J. Wysocki wrote: > > > On Friday, November 21, 2014 03:11:51 PM Aaron Lu wrote: > > >> + if (!result) { > > >> + status = acpi_install_address_space_handler( > > >> + ACPI_HANDLE(parent), ACPI_ADR_SPACE_GPIO, > > >> + intel_xpower_pmic_gpio_handler, NULL, NULL); > > > > > > So here we have a problem, because we can't unregister the opregion handler > > > registered above if this fails. Not nice. > > > > I'm not correct in the cover letter, the actual problem with operation > > region remove is with module unload, it happens like this: > > > > The acpi_remove_address_space_handler doesn't wait for the current > > running handler to return, so if we call > > acpi_remove_address_space_handler in a module's exit function, the > > handler's memory will be freed and the running handler will access to > > a no longer valid memory place. > > > > So as long as we can make sure the handler will not go away from the > > memory, we are safe. > > This only means that address space handlers cannot be removed from kernel > modules. > > Lv was trying to add a wrapper for that some time ago, maybe it's a good > idea to revive that? I may fix the issue in ACPICA, but it looks like that it will cost time to discuss. So I also think it is better to take the wrapper now. I'll hand the patch to Aaron to let him do a test on it before posting it again. Thanks and best regards -Lv > > With this said, the updated patch is here: > > > > From: Aaron Lu <aaron.lu@xxxxxxxxx> > > Date: Mon, 20 Oct 2014 17:06:20 +0800 > > Subject: [PATCH 3/3] ACPI / PMIC: AXP288: support virtual GPIO in ACPI table > > > > The same virtual GPIO strategy is also used for the AXP288 PMIC in that > > various control methods that are used to do power rail handling and > > sensor reading/setting will touch GPIO fields defined under the PMIC > > device. The GPIO fileds are only defined by the ACPI code while the > > actual hardware doesn't really have a GPIO controller, but to make those > > control method execution succeed, we have to install a GPIO handler for > > the PMIC device handle. Since we do not need the virtual GPIO strategy, > > we can simply do nothing in that handler. > > > > Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx> > > --- > > drivers/acpi/pmic/intel_pmic_xpower.c | 30 ++++++++++++++++++++++++++---- > > 1 file changed, 26 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/acpi/pmic/intel_pmic_xpower.c b/drivers/acpi/pmic/intel_pmic_xpower.c > > index 795ca073db08..9ec57ebd81c9 100644 > > --- a/drivers/acpi/pmic/intel_pmic_xpower.c > > +++ b/drivers/acpi/pmic/intel_pmic_xpower.c > > @@ -220,13 +220,35 @@ static struct intel_pmic_opregion_data intel_xpower_pmic_opregion_data = { > > .thermal_table_count = ARRAY_SIZE(thermal_table), > > }; > > > > +static acpi_status intel_xpower_pmic_gpio_handler(u32 function, > > + acpi_physical_address address, u32 bit_width, u64 *value, > > + void *handler_context, void *region_context) > > +{ > > + return AE_OK; > > +} > > > > static int intel_xpower_pmic_opregion_probe(struct platform_device *pdev) > > { > > - struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent); > > - return intel_pmic_install_opregion_handler(&pdev->dev, > > - ACPI_HANDLE(pdev->dev.parent), axp20x->regmap, > > - &intel_xpower_pmic_opregion_data); > > + struct device *parent = pdev->dev.parent; > > + struct axp20x_dev *axp20x = dev_get_drvdata(parent); > > + acpi_status status; > > + int result; > > + > > + status = acpi_install_address_space_handler(ACPI_HANDLE(parent), > > + ACPI_ADR_SPACE_GPIO, intel_xpower_pmic_gpio_handler, > > + NULL, NULL); > > + if (ACPI_FAILURE(status)) > > + return -ENODEV; > > + > > + result = intel_pmic_install_opregion_handler(&pdev->dev, > > + ACPI_HANDLE(parent), axp20x->regmap, > > + &intel_xpower_pmic_opregion_data); > > + if (result) > > + acpi_remove_address_space_handler(ACPI_HANDLE(parent), > > + ACPI_ADR_SPACE_GPIO, > > + intel_xpower_pmic_gpio_handler); > > + > > + return result; > > } > > > > static struct platform_driver intel_xpower_pmic_opregion_driver = { > > > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
