| Message ID | 20200827085911.944899-2-enric.balletbo@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bridge: ps8640: Make sure all needed is powered to get the EDID | expand |
Hi Enric, On Thu, 27 Aug 2020 10:59:11 +0200 Enric Balletbo i Serra <enric.balletbo@collabora.com> wrote: > The get_edid() callback can be triggered anytime by an ioctl, i.e > > drm_mode_getconnector (ioctl) > -> drm_helper_probe_single_connector_modes > -> drm_bridge_connector_get_modes > -> ps8640_bridge_get_edid > > Actually if the bridge pre_enable() function was not called before > get_edid(), the driver will not be able to get the EDID properly and > display will not work until a second get_edid() call is issued and if > pre_enable() is called before. The side effect of this, for example, > is that you see anything when `Frecon` starts, neither the splash > screen, until the graphical session manager starts. > > To fix this we need to make sure that all we need is enabled before > reading the EDID. This means the following: > > 1. If get_edid() is called before having the device powered we need to > power on the device. In such case, the driver will power off again > the device. > > 2. If get_edid() is called after having the device powered, all should > just work. We added a powered flag in order to avoid recurrent > calls to ps8640_bridge_poweron() and unneeded delays. > > 3. This seems to be specific for this device, but we need to make sure > the panel is powered on before do a power on cycle on this device. > Otherwise the device fails to retrieve the EDID. > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> > --- > > Changes in v3: > - Make poweron/poweroff and pre_enable/post_disable reverse one to > each other (Sam Ravnborg) > > Changes in v2: > - Use drm_bridge_chain_pre_enable/post_disable() helpers (Sam > Ravnborg) > > drivers/gpu/drm/bridge/parade-ps8640.c | 68 > ++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 10 > deletions(-) > > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c > b/drivers/gpu/drm/bridge/parade-ps8640.c index > 9f7b7a9c53c5..7bd0affa057a 100644 --- > a/drivers/gpu/drm/bridge/parade-ps8640.c +++ > b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -65,6 +65,7 @@ struct > ps8640 { struct regulator_bulk_data supplies[2]; > struct gpio_desc *gpio_reset; > struct gpio_desc *gpio_powerdown; > + bool powered; > }; > > static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e) > @@ -91,13 +92,15 @@ static int ps8640_bridge_vdo_control(struct > ps8640 *ps_bridge, return 0; > } > > -static void ps8640_pre_enable(struct drm_bridge *bridge) > +static void ps8640_bridge_poweron(struct ps8640 *ps_bridge) > { > - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > struct i2c_client *client = ps_bridge->page[PAGE2_TOP_CNTL]; > unsigned long timeout; > int ret, status; > > + if (ps_bridge->powered) > + return; > + > ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies), > ps_bridge->supplies); > if (ret < 0) { > @@ -152,10 +155,6 @@ static void ps8640_pre_enable(struct drm_bridge > *bridge) goto err_regulators_disable; > } > > - ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); > - if (ret) > - goto err_regulators_disable; > - > /* Switch access edp panel's edid through i2c */ > ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS, > I2C_BYPASS_EN); > @@ -164,6 +163,8 @@ static void ps8640_pre_enable(struct drm_bridge > *bridge) goto err_regulators_disable; > } > > + ps_bridge->powered = true; > + > return; > > err_regulators_disable: > @@ -171,12 +172,12 @@ static void ps8640_pre_enable(struct drm_bridge > *bridge) ps_bridge->supplies); > } > > -static void ps8640_post_disable(struct drm_bridge *bridge) > +static void ps8640_bridge_poweroff(struct ps8640 *ps_bridge) > { > - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > int ret; > > - ps8640_bridge_vdo_control(ps_bridge, DISABLE); > + if (!ps_bridge->powered) > + return; > > gpiod_set_value(ps_bridge->gpio_reset, 1); > gpiod_set_value(ps_bridge->gpio_powerdown, 1); > @@ -184,6 +185,28 @@ static void ps8640_post_disable(struct > drm_bridge *bridge) ps_bridge->supplies); > if (ret < 0) > DRM_ERROR("cannot disable regulators %d\n", ret); > + > + ps_bridge->powered = false; > +} > + > +static void ps8640_pre_enable(struct drm_bridge *bridge) > +{ > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + int ret; > + > + ps8640_bridge_poweron(ps_bridge); > + > + ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); > + if (ret < 0) > + ps8640_bridge_poweroff(ps_bridge); > +} > + > +static void ps8640_post_disable(struct drm_bridge *bridge) > +{ > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + > + ps8640_bridge_vdo_control(ps_bridge, DISABLE); > + ps8640_bridge_poweroff(ps_bridge); > } > > static int ps8640_bridge_attach(struct drm_bridge *bridge, > @@ -249,9 +272,34 @@ static struct edid > *ps8640_bridge_get_edid(struct drm_bridge *bridge, struct > drm_connector *connector) { > struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + bool poweroff = !ps_bridge->powered; > + struct edid *edid; > + > + /* > + * When we end calling get_edid() triggered by an ioctl, i.e > + * > + * drm_mode_getconnector (ioctl) > + * -> drm_helper_probe_single_connector_modes > + * -> drm_bridge_connector_get_modes > + * -> ps8640_bridge_get_edid > + * > + * We need to make sure that what we need is enabled before > reading > + * EDID, for this chip, we need to do a full poweron, > otherwise it will > + * fail. > + */ > + drm_bridge_chain_pre_enable(bridge); Are we sure that pre_enable is always good enough to get the EDID? I know that we only have support for ps8640 on the MT8173 SoC which works only with pre_enable, but I think a more scalable solution would be to call drm_bridge_chain_pre_enable / drm_bridge_chain_enable here, and drm_bridge_chain_post_disable / drm_bridge_chain_disable when disabling the chain. If this is not a concern and we are sure that pre_enable will always work (especially on newer boards), then please ignore my comment. Other than this, everything looks fine. > > - return drm_get_edid(connector, > + edid = drm_get_edid(connector, > ps_bridge->page[PAGE0_DP_CNTL]->adapter); > + > + /* > + * If we call the get_edid() function without having enabled > the chip > + * before, return the chip to its original power state. > + */ > + if (poweroff) > + drm_bridge_chain_post_disable(bridge); > + > + return edid; > } > > static const struct drm_bridge_funcs ps8640_bridge_funcs = { -Bilal
Hi Bilal, On 31/8/20 11:32, Bilal Wasim wrote: > > Hi Enric, > > On Thu, 27 Aug 2020 10:59:11 +0200 > Enric Balletbo i Serra <enric.balletbo@collabora.com> wrote: > >> The get_edid() callback can be triggered anytime by an ioctl, i.e >> >> drm_mode_getconnector (ioctl) >> -> drm_helper_probe_single_connector_modes >> -> drm_bridge_connector_get_modes >> -> ps8640_bridge_get_edid >> >> Actually if the bridge pre_enable() function was not called before >> get_edid(), the driver will not be able to get the EDID properly and >> display will not work until a second get_edid() call is issued and if >> pre_enable() is called before. The side effect of this, for example, >> is that you see anything when `Frecon` starts, neither the splash >> screen, until the graphical session manager starts. >> >> To fix this we need to make sure that all we need is enabled before >> reading the EDID. This means the following: >> >> 1. If get_edid() is called before having the device powered we need to >> power on the device. In such case, the driver will power off again >> the device. >> >> 2. If get_edid() is called after having the device powered, all should >> just work. We added a powered flag in order to avoid recurrent >> calls to ps8640_bridge_poweron() and unneeded delays. >> >> 3. This seems to be specific for this device, but we need to make sure >> the panel is powered on before do a power on cycle on this device. >> Otherwise the device fails to retrieve the EDID. >> >> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> >> --- >> >> Changes in v3: >> - Make poweron/poweroff and pre_enable/post_disable reverse one to >> each other (Sam Ravnborg) >> >> Changes in v2: >> - Use drm_bridge_chain_pre_enable/post_disable() helpers (Sam >> Ravnborg) >> >> drivers/gpu/drm/bridge/parade-ps8640.c | 68 >> ++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 10 >> deletions(-) >> >> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c >> b/drivers/gpu/drm/bridge/parade-ps8640.c index >> 9f7b7a9c53c5..7bd0affa057a 100644 --- >> a/drivers/gpu/drm/bridge/parade-ps8640.c +++ >> b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -65,6 +65,7 @@ struct >> ps8640 { struct regulator_bulk_data supplies[2]; >> struct gpio_desc *gpio_reset; >> struct gpio_desc *gpio_powerdown; >> + bool powered; >> }; >> >> static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e) >> @@ -91,13 +92,15 @@ static int ps8640_bridge_vdo_control(struct >> ps8640 *ps_bridge, return 0; >> } >> >> -static void ps8640_pre_enable(struct drm_bridge *bridge) >> +static void ps8640_bridge_poweron(struct ps8640 *ps_bridge) >> { >> - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); >> struct i2c_client *client = ps_bridge->page[PAGE2_TOP_CNTL]; >> unsigned long timeout; >> int ret, status; >> >> + if (ps_bridge->powered) >> + return; >> + >> ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies), >> ps_bridge->supplies); >> if (ret < 0) { >> @@ -152,10 +155,6 @@ static void ps8640_pre_enable(struct drm_bridge >> *bridge) goto err_regulators_disable; >> } >> >> - ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); >> - if (ret) >> - goto err_regulators_disable; >> - >> /* Switch access edp panel's edid through i2c */ >> ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS, >> I2C_BYPASS_EN); >> @@ -164,6 +163,8 @@ static void ps8640_pre_enable(struct drm_bridge >> *bridge) goto err_regulators_disable; >> } >> >> + ps_bridge->powered = true; >> + >> return; >> >> err_regulators_disable: >> @@ -171,12 +172,12 @@ static void ps8640_pre_enable(struct drm_bridge >> *bridge) ps_bridge->supplies); >> } >> >> -static void ps8640_post_disable(struct drm_bridge *bridge) >> +static void ps8640_bridge_poweroff(struct ps8640 *ps_bridge) >> { >> - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); >> int ret; >> >> - ps8640_bridge_vdo_control(ps_bridge, DISABLE); >> + if (!ps_bridge->powered) >> + return; >> >> gpiod_set_value(ps_bridge->gpio_reset, 1); >> gpiod_set_value(ps_bridge->gpio_powerdown, 1); >> @@ -184,6 +185,28 @@ static void ps8640_post_disable(struct >> drm_bridge *bridge) ps_bridge->supplies); >> if (ret < 0) >> DRM_ERROR("cannot disable regulators %d\n", ret); >> + >> + ps_bridge->powered = false; >> +} >> + >> +static void ps8640_pre_enable(struct drm_bridge *bridge) >> +{ >> + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); >> + int ret; >> + >> + ps8640_bridge_poweron(ps_bridge); >> + >> + ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); >> + if (ret < 0) >> + ps8640_bridge_poweroff(ps_bridge); >> +} >> + >> +static void ps8640_post_disable(struct drm_bridge *bridge) >> +{ >> + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); >> + >> + ps8640_bridge_vdo_control(ps_bridge, DISABLE); >> + ps8640_bridge_poweroff(ps_bridge); >> } >> >> static int ps8640_bridge_attach(struct drm_bridge *bridge, >> @@ -249,9 +272,34 @@ static struct edid >> *ps8640_bridge_get_edid(struct drm_bridge *bridge, struct >> drm_connector *connector) { >> struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); >> + bool poweroff = !ps_bridge->powered; >> + struct edid *edid; >> + >> + /* >> + * When we end calling get_edid() triggered by an ioctl, i.e >> + * >> + * drm_mode_getconnector (ioctl) >> + * -> drm_helper_probe_single_connector_modes >> + * -> drm_bridge_connector_get_modes >> + * -> ps8640_bridge_get_edid >> + * >> + * We need to make sure that what we need is enabled before >> reading >> + * EDID, for this chip, we need to do a full poweron, >> otherwise it will >> + * fail. >> + */ >> + drm_bridge_chain_pre_enable(bridge); > > Are we sure that pre_enable is always good enough to get the EDID? I > know that we only have support for ps8640 on the MT8173 SoC which works > only with pre_enable, but I think a more scalable solution would be to > call drm_bridge_chain_pre_enable / drm_bridge_chain_enable here, and > drm_bridge_chain_post_disable / drm_bridge_chain_disable when disabling > the chain. If this is not a concern and we are sure that pre_enable > will always work (especially on newer boards), then please ignore my > comment. > Not a drm_bridge API expert, and sometimes I am confused about it, but, from what I know, I'm pretty sure that we _don't_ want to call drm_bridge_chain_enable(). The call drm_bridge_chain_pre_enable() will end with calling drm_panel_prepare(), which, as per documentation: * Calling this function will enable power and deassert any reset signals to * the panel. After this has completed it is possible to communicate with any * integrated circuitry via a command bus. Calling drm_bridge_chain_enable() too will end calling drm_panel_enable(), and, as per documentation: * Calling this function will cause the panel display drivers to be turned on * and the backlight to be enabled. Content will be visible on screen after * this call completes Which can trigger a screen flickering and enable more things that what we want. Reading the EDID should be possible just after a call of drm_bridge_prepare(). Enable the panel should not be required. Cheers, Enric > Other than this, everything looks fine. > >> >> - return drm_get_edid(connector, >> + edid = drm_get_edid(connector, >> ps_bridge->page[PAGE0_DP_CNTL]->adapter); >> + >> + /* >> + * If we call the get_edid() function without having enabled >> the chip >> + * before, return the chip to its original power state. >> + */ >> + if (poweroff) >> + drm_bridge_chain_post_disable(bridge); >> + >> + return edid; >> } >> >> static const struct drm_bridge_funcs ps8640_bridge_funcs = { > > -Bilal >
Hi Enric, On Thu, 27 Aug 2020 10:59:11 +0200 Enric Balletbo i Serra <enric.balletbo@collabora.com> wrote: > The get_edid() callback can be triggered anytime by an ioctl, i.e > > drm_mode_getconnector (ioctl) > -> drm_helper_probe_single_connector_modes > -> drm_bridge_connector_get_modes > -> ps8640_bridge_get_edid > > Actually if the bridge pre_enable() function was not called before > get_edid(), the driver will not be able to get the EDID properly and > display will not work until a second get_edid() call is issued and if > pre_enable() is called before. The side effect of this, for example, > is that you see anything when `Frecon` starts, neither the splash > screen, until the graphical session manager starts. > > To fix this we need to make sure that all we need is enabled before > reading the EDID. This means the following: > > 1. If get_edid() is called before having the device powered we need to > power on the device. In such case, the driver will power off again > the device. > > 2. If get_edid() is called after having the device powered, all should > just work. We added a powered flag in order to avoid recurrent > calls to ps8640_bridge_poweron() and unneeded delays. > > 3. This seems to be specific for this device, but we need to make sure > the panel is powered on before do a power on cycle on this device. > Otherwise the device fails to retrieve the EDID. > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> > --- > > Changes in v3: > - Make poweron/poweroff and pre_enable/post_disable reverse one to > each other (Sam Ravnborg) > > Changes in v2: > - Use drm_bridge_chain_pre_enable/post_disable() helpers (Sam > Ravnborg) > > drivers/gpu/drm/bridge/parade-ps8640.c | 68 > ++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 10 > deletions(-) > > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c > b/drivers/gpu/drm/bridge/parade-ps8640.c index > 9f7b7a9c53c5..7bd0affa057a 100644 --- > a/drivers/gpu/drm/bridge/parade-ps8640.c +++ > b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -65,6 +65,7 @@ struct > ps8640 { struct regulator_bulk_data supplies[2]; > struct gpio_desc *gpio_reset; > struct gpio_desc *gpio_powerdown; > + bool powered; > }; > > static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e) > @@ -91,13 +92,15 @@ static int ps8640_bridge_vdo_control(struct > ps8640 *ps_bridge, return 0; > } > > -static void ps8640_pre_enable(struct drm_bridge *bridge) > +static void ps8640_bridge_poweron(struct ps8640 *ps_bridge) > { > - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > struct i2c_client *client = ps_bridge->page[PAGE2_TOP_CNTL]; > unsigned long timeout; > int ret, status; > > + if (ps_bridge->powered) > + return; > + > ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies), > ps_bridge->supplies); > if (ret < 0) { > @@ -152,10 +155,6 @@ static void ps8640_pre_enable(struct drm_bridge > *bridge) goto err_regulators_disable; > } > > - ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); > - if (ret) > - goto err_regulators_disable; > - > /* Switch access edp panel's edid through i2c */ > ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS, > I2C_BYPASS_EN); > @@ -164,6 +163,8 @@ static void ps8640_pre_enable(struct drm_bridge > *bridge) goto err_regulators_disable; > } > > + ps_bridge->powered = true; > + > return; > > err_regulators_disable: > @@ -171,12 +172,12 @@ static void ps8640_pre_enable(struct drm_bridge > *bridge) ps_bridge->supplies); > } > > -static void ps8640_post_disable(struct drm_bridge *bridge) > +static void ps8640_bridge_poweroff(struct ps8640 *ps_bridge) > { > - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > int ret; > > - ps8640_bridge_vdo_control(ps_bridge, DISABLE); > + if (!ps_bridge->powered) > + return; > > gpiod_set_value(ps_bridge->gpio_reset, 1); > gpiod_set_value(ps_bridge->gpio_powerdown, 1); > @@ -184,6 +185,28 @@ static void ps8640_post_disable(struct > drm_bridge *bridge) ps_bridge->supplies); > if (ret < 0) > DRM_ERROR("cannot disable regulators %d\n", ret); > + > + ps_bridge->powered = false; > +} > + > +static void ps8640_pre_enable(struct drm_bridge *bridge) > +{ > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + int ret; > + > + ps8640_bridge_poweron(ps_bridge); > + > + ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); > + if (ret < 0) > + ps8640_bridge_poweroff(ps_bridge); > +} > + > +static void ps8640_post_disable(struct drm_bridge *bridge) > +{ > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + > + ps8640_bridge_vdo_control(ps_bridge, DISABLE); > + ps8640_bridge_poweroff(ps_bridge); > } > > static int ps8640_bridge_attach(struct drm_bridge *bridge, > @@ -249,9 +272,34 @@ static struct edid > *ps8640_bridge_get_edid(struct drm_bridge *bridge, struct > drm_connector *connector) { > struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + bool poweroff = !ps_bridge->powered; > + struct edid *edid; > + > + /* > + * When we end calling get_edid() triggered by an ioctl, i.e > + * > + * drm_mode_getconnector (ioctl) > + * -> drm_helper_probe_single_connector_modes > + * -> drm_bridge_connector_get_modes > + * -> ps8640_bridge_get_edid > + * > + * We need to make sure that what we need is enabled before > reading > + * EDID, for this chip, we need to do a full poweron, > otherwise it will > + * fail. > + */ > + drm_bridge_chain_pre_enable(bridge); > > - return drm_get_edid(connector, > + edid = drm_get_edid(connector, > ps_bridge->page[PAGE0_DP_CNTL]->adapter); > + > + /* > + * If we call the get_edid() function without having enabled > the chip > + * before, return the chip to its original power state. > + */ > + if (poweroff) > + drm_bridge_chain_post_disable(bridge); > + > + return edid; > } > > static const struct drm_bridge_funcs ps8640_bridge_funcs = { I was able to apply this patch successfully to drm-misc-next / master - For Master, I had to apply your patches which have already made it to drm-misc-next. I was able to build / test successfully with Elm Chromebook. It seems that the kernel bot has reported a false positive. Tested-by: Bilal Wasim <bwasim.lkml@gmail.com> -Bilal
On 27/08/2020 10:59, Enric Balletbo i Serra wrote: > The get_edid() callback can be triggered anytime by an ioctl, i.e > > drm_mode_getconnector (ioctl) > -> drm_helper_probe_single_connector_modes > -> drm_bridge_connector_get_modes > -> ps8640_bridge_get_edid > > Actually if the bridge pre_enable() function was not called before > get_edid(), the driver will not be able to get the EDID properly and > display will not work until a second get_edid() call is issued and if > pre_enable() is called before. The side effect of this, for example, is > that you see anything when `Frecon` starts, neither the splash screen, > until the graphical session manager starts. > > To fix this we need to make sure that all we need is enabled before > reading the EDID. This means the following: > > 1. If get_edid() is called before having the device powered we need to > power on the device. In such case, the driver will power off again the > device. > > 2. If get_edid() is called after having the device powered, all should > just work. We added a powered flag in order to avoid recurrent calls > to ps8640_bridge_poweron() and unneeded delays. > > 3. This seems to be specific for this device, but we need to make sure > the panel is powered on before do a power on cycle on this device. > Otherwise the device fails to retrieve the EDID. > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> > --- > > Changes in v3: > - Make poweron/poweroff and pre_enable/post_disable reverse one to each other (Sam Ravnborg) > > Changes in v2: > - Use drm_bridge_chain_pre_enable/post_disable() helpers (Sam Ravnborg) > > drivers/gpu/drm/bridge/parade-ps8640.c | 68 ++++++++++++++++++++++---- > 1 file changed, 58 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c > index 9f7b7a9c53c5..7bd0affa057a 100644 > --- a/drivers/gpu/drm/bridge/parade-ps8640.c > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c > @@ -65,6 +65,7 @@ struct ps8640 { > struct regulator_bulk_data supplies[2]; > struct gpio_desc *gpio_reset; > struct gpio_desc *gpio_powerdown; > + bool powered; > }; > > static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e) > @@ -91,13 +92,15 @@ static int ps8640_bridge_vdo_control(struct ps8640 *ps_bridge, > return 0; > } > > -static void ps8640_pre_enable(struct drm_bridge *bridge) > +static void ps8640_bridge_poweron(struct ps8640 *ps_bridge) > { > - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > struct i2c_client *client = ps_bridge->page[PAGE2_TOP_CNTL]; > unsigned long timeout; > int ret, status; > > + if (ps_bridge->powered) > + return; > + > ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies), > ps_bridge->supplies); > if (ret < 0) { > @@ -152,10 +155,6 @@ static void ps8640_pre_enable(struct drm_bridge *bridge) > goto err_regulators_disable; > } > > - ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); > - if (ret) > - goto err_regulators_disable; > - > /* Switch access edp panel's edid through i2c */ > ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS, > I2C_BYPASS_EN); > @@ -164,6 +163,8 @@ static void ps8640_pre_enable(struct drm_bridge *bridge) > goto err_regulators_disable; > } > > + ps_bridge->powered = true; > + > return; > > err_regulators_disable: > @@ -171,12 +172,12 @@ static void ps8640_pre_enable(struct drm_bridge *bridge) > ps_bridge->supplies); > } > > -static void ps8640_post_disable(struct drm_bridge *bridge) > +static void ps8640_bridge_poweroff(struct ps8640 *ps_bridge) > { > - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > int ret; > > - ps8640_bridge_vdo_control(ps_bridge, DISABLE); > + if (!ps_bridge->powered) > + return; > > gpiod_set_value(ps_bridge->gpio_reset, 1); > gpiod_set_value(ps_bridge->gpio_powerdown, 1); > @@ -184,6 +185,28 @@ static void ps8640_post_disable(struct drm_bridge *bridge) > ps_bridge->supplies); > if (ret < 0) > DRM_ERROR("cannot disable regulators %d\n", ret); > + > + ps_bridge->powered = false; > +} > + > +static void ps8640_pre_enable(struct drm_bridge *bridge) > +{ > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + int ret; > + > + ps8640_bridge_poweron(ps_bridge); > + > + ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); > + if (ret < 0) > + ps8640_bridge_poweroff(ps_bridge); > +} > + > +static void ps8640_post_disable(struct drm_bridge *bridge) > +{ > + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + > + ps8640_bridge_vdo_control(ps_bridge, DISABLE); > + ps8640_bridge_poweroff(ps_bridge); > } > > static int ps8640_bridge_attach(struct drm_bridge *bridge, > @@ -249,9 +272,34 @@ static struct edid *ps8640_bridge_get_edid(struct drm_bridge *bridge, > struct drm_connector *connector) > { > struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); > + bool poweroff = !ps_bridge->powered; > + struct edid *edid; > + > + /* > + * When we end calling get_edid() triggered by an ioctl, i.e > + * > + * drm_mode_getconnector (ioctl) > + * -> drm_helper_probe_single_connector_modes > + * -> drm_bridge_connector_get_modes > + * -> ps8640_bridge_get_edid > + * > + * We need to make sure that what we need is enabled before reading > + * EDID, for this chip, we need to do a full poweron, otherwise it will > + * fail. > + */ > + drm_bridge_chain_pre_enable(bridge); > > - return drm_get_edid(connector, > + edid = drm_get_edid(connector, > ps_bridge->page[PAGE0_DP_CNTL]->adapter); > + > + /* > + * If we call the get_edid() function without having enabled the chip > + * before, return the chip to its original power state. > + */ > + if (poweroff) > + drm_bridge_chain_post_disable(bridge); > + > + return edid; > } > > static const struct drm_bridge_funcs ps8640_bridge_funcs = { > Acked-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c index 9f7b7a9c53c5..7bd0affa057a 100644 --- a/drivers/gpu/drm/bridge/parade-ps8640.c +++ b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -65,6 +65,7 @@ struct ps8640 { struct regulator_bulk_data supplies[2]; struct gpio_desc *gpio_reset; struct gpio_desc *gpio_powerdown; + bool powered; }; static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e) @@ -91,13 +92,15 @@ static int ps8640_bridge_vdo_control(struct ps8640 *ps_bridge, return 0; } -static void ps8640_pre_enable(struct drm_bridge *bridge) +static void ps8640_bridge_poweron(struct ps8640 *ps_bridge) { - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); struct i2c_client *client = ps_bridge->page[PAGE2_TOP_CNTL]; unsigned long timeout; int ret, status; + if (ps_bridge->powered) + return; + ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies), ps_bridge->supplies); if (ret < 0) { @@ -152,10 +155,6 @@ static void ps8640_pre_enable(struct drm_bridge *bridge) goto err_regulators_disable; } - ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); - if (ret) - goto err_regulators_disable; - /* Switch access edp panel's edid through i2c */ ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS, I2C_BYPASS_EN); @@ -164,6 +163,8 @@ static void ps8640_pre_enable(struct drm_bridge *bridge) goto err_regulators_disable; } + ps_bridge->powered = true; + return; err_regulators_disable: @@ -171,12 +172,12 @@ static void ps8640_pre_enable(struct drm_bridge *bridge) ps_bridge->supplies); } -static void ps8640_post_disable(struct drm_bridge *bridge) +static void ps8640_bridge_poweroff(struct ps8640 *ps_bridge) { - struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); int ret; - ps8640_bridge_vdo_control(ps_bridge, DISABLE); + if (!ps_bridge->powered) + return; gpiod_set_value(ps_bridge->gpio_reset, 1); gpiod_set_value(ps_bridge->gpio_powerdown, 1); @@ -184,6 +185,28 @@ static void ps8640_post_disable(struct drm_bridge *bridge) ps_bridge->supplies); if (ret < 0) DRM_ERROR("cannot disable regulators %d\n", ret); + + ps_bridge->powered = false; +} + +static void ps8640_pre_enable(struct drm_bridge *bridge) +{ + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); + int ret; + + ps8640_bridge_poweron(ps_bridge); + + ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE); + if (ret < 0) + ps8640_bridge_poweroff(ps_bridge); +} + +static void ps8640_post_disable(struct drm_bridge *bridge) +{ + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); + + ps8640_bridge_vdo_control(ps_bridge, DISABLE); + ps8640_bridge_poweroff(ps_bridge); } static int ps8640_bridge_attach(struct drm_bridge *bridge, @@ -249,9 +272,34 @@ static struct edid *ps8640_bridge_get_edid(struct drm_bridge *bridge, struct drm_connector *connector) { struct ps8640 *ps_bridge = bridge_to_ps8640(bridge); + bool poweroff = !ps_bridge->powered; + struct edid *edid; + + /* + * When we end calling get_edid() triggered by an ioctl, i.e + * + * drm_mode_getconnector (ioctl) + * -> drm_helper_probe_single_connector_modes + * -> drm_bridge_connector_get_modes + * -> ps8640_bridge_get_edid + * + * We need to make sure that what we need is enabled before reading + * EDID, for this chip, we need to do a full poweron, otherwise it will + * fail. + */ + drm_bridge_chain_pre_enable(bridge); - return drm_get_edid(connector, + edid = drm_get_edid(connector, ps_bridge->page[PAGE0_DP_CNTL]->adapter); + + /* + * If we call the get_edid() function without having enabled the chip + * before, return the chip to its original power state. + */ + if (poweroff) + drm_bridge_chain_post_disable(bridge); + + return edid; } static const struct drm_bridge_funcs ps8640_bridge_funcs = {
The get_edid() callback can be triggered anytime by an ioctl, i.e drm_mode_getconnector (ioctl) -> drm_helper_probe_single_connector_modes -> drm_bridge_connector_get_modes -> ps8640_bridge_get_edid Actually if the bridge pre_enable() function was not called before get_edid(), the driver will not be able to get the EDID properly and display will not work until a second get_edid() call is issued and if pre_enable() is called before. The side effect of this, for example, is that you see anything when `Frecon` starts, neither the splash screen, until the graphical session manager starts. To fix this we need to make sure that all we need is enabled before reading the EDID. This means the following: 1. If get_edid() is called before having the device powered we need to power on the device. In such case, the driver will power off again the device. 2. If get_edid() is called after having the device powered, all should just work. We added a powered flag in order to avoid recurrent calls to ps8640_bridge_poweron() and unneeded delays. 3. This seems to be specific for this device, but we need to make sure the panel is powered on before do a power on cycle on this device. Otherwise the device fails to retrieve the EDID. Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> --- Changes in v3: - Make poweron/poweroff and pre_enable/post_disable reverse one to each other (Sam Ravnborg) Changes in v2: - Use drm_bridge_chain_pre_enable/post_disable() helpers (Sam Ravnborg) drivers/gpu/drm/bridge/parade-ps8640.c | 68 ++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 10 deletions(-)