Some panels support backlight control over DP AUX channel using
VESA's standard backlight control interface.
Using new DRM eDP backlight helpers, add support to create and
register a backlight for those panels in drm_panel to simplify
the panel drivers.
The panel driver with access to "struct drm_dp_aux" can create and
register a backlight device using following code snippet in its
probe() function:
err = drm_panel_dp_aux_backlight(panel, aux);
if (err)
return err;
Then drm_panel will handle backlight_(enable|disable) calls
similar to the case when drm_panel_of_backlight() is used.
Currently, we are not supporting one feature where the source
device can combine the backlight brightness levels set through
DP AUX and the BL_PWM_DIM eDP connector pin. Since it's not
required for the basic backlight controls, it can be added later.
Signed-off-by: Rajeev Nandan <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Reviewed-by: Lyude Paul <[email protected]>
---
Changes in v5:
- New
Changes in v6:
- Fixed ordering of memory allocation (Douglas)
- Updated word wrapping in a comment (Douglas)
Changes in v8:
- Now using backlight_is_blank() to get the backlight blank status (Sam Ravnborg)
drivers/gpu/drm/drm_panel.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
include/drm/drm_panel.h | 15 ++++--
2 files changed, 119 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index f634371..4fa1e3b 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -26,12 +26,20 @@
#include <linux/module.h>
#include <drm/drm_crtc.h>
+#include <drm/drm_dp_helper.h>
#include <drm/drm_panel.h>
#include <drm/drm_print.h>
static DEFINE_MUTEX(panel_lock);
static LIST_HEAD(panel_list);
+struct dp_aux_backlight {
+ struct backlight_device *base;
+ struct drm_dp_aux *aux;
+ struct drm_edp_backlight_info info;
+ bool enabled;
+};
+
/**
* DOC: drm panel
*
@@ -342,6 +350,106 @@ int drm_panel_of_backlight(struct drm_panel *panel)
return 0;
}
EXPORT_SYMBOL(drm_panel_of_backlight);
+
+static int dp_aux_backlight_update_status(struct backlight_device *bd)
+{
+ struct dp_aux_backlight *bl = bl_get_data(bd);
+ u16 brightness = backlight_get_brightness(bd);
+ int ret = 0;
+
+ if (!backlight_is_blank(bd)) {
+ if (!bl->enabled) {
+ drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
+ bl->enabled = true;
+ return 0;
+ }
+ ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
+ } else {
+ if (bl->enabled) {
+ drm_edp_backlight_disable(bl->aux, &bl->info);
+ bl->enabled = false;
+ }
+ }
+
+ return ret;
+}
+
+static const struct backlight_ops dp_aux_bl_ops = {
+ .update_status = dp_aux_backlight_update_status,
+};
+
+/**
+ * drm_panel_dp_aux_backlight - create and use DP AUX backlight
+ * @panel: DRM panel
+ * @aux: The DP AUX channel to use
+ *
+ * Use this function to create and handle backlight if your panel
+ * supports backlight control over DP AUX channel using DPCD
+ * registers as per VESA's standard backlight control interface.
+ *
+ * When the panel is enabled backlight will be enabled after a
+ * successful call to &drm_panel_funcs.enable()
+ *
+ * When the panel is disabled backlight will be disabled before the
+ * call to &drm_panel_funcs.disable().
+ *
+ * A typical implementation for a panel driver supporting backlight
+ * control over DP AUX will call this function at probe time.
+ * Backlight will then be handled transparently without requiring
+ * any intervention from the driver.
+ *
+ * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init().
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux)
+{
+ struct dp_aux_backlight *bl;
+ struct backlight_properties props = { 0 };
+ u16 current_level;
+ u8 current_mode;
+ u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
+ int ret;
+
+ if (!panel || !panel->dev || !aux)
+ return -EINVAL;
+
+ ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,
+ EDP_DISPLAY_CTL_CAP_SIZE);
+ if (ret < 0)
+ return ret;
+
+ if (!drm_edp_backlight_supported(edp_dpcd)) {
+ DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n");
+ return 0;
+ }
+
+ bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL);
+ if (!bl)
+ return -ENOMEM;
+
+ bl->aux = aux;
+
+ ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,
+ ¤t_level, ¤t_mode);
+ if (ret < 0)
+ return ret;
+
+ props.type = BACKLIGHT_RAW;
+ props.brightness = current_level;
+ props.max_brightness = bl->info.max;
+
+ bl->base = devm_backlight_device_register(panel->dev, "dp_aux_backlight",
+ panel->dev, bl,
+ &dp_aux_bl_ops, &props);
+ if (IS_ERR(bl->base))
+ return PTR_ERR(bl->base);
+
+ panel->backlight = bl->base;
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_panel_dp_aux_backlight);
#endif
MODULE_AUTHOR("Thierry Reding <[email protected]>");
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 33605c3..3ebfaa6 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -32,6 +32,7 @@ struct backlight_device;
struct device_node;
struct drm_connector;
struct drm_device;
+struct drm_dp_aux;
struct drm_panel;
struct display_timing;
@@ -64,8 +65,8 @@ enum drm_panel_orientation;
* the panel. This is the job of the .unprepare() function.
*
* Backlight can be handled automatically if configured using
- * drm_panel_of_backlight(). Then the driver does not need to implement the
- * functionality to enable/disable backlight.
+ * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
+ * does not need to implement the functionality to enable/disable backlight.
*/
struct drm_panel_funcs {
/**
@@ -144,8 +145,8 @@ struct drm_panel {
* Backlight device, used to turn on backlight after the call
* to enable(), and to turn off backlight before the call to
* disable().
- * backlight is set by drm_panel_of_backlight() and drivers
- * shall not assign it.
+ * backlight is set by drm_panel_of_backlight() or
+ * drm_panel_dp_aux_backlight() and drivers shall not assign it.
*/
struct backlight_device *backlight;
@@ -208,11 +209,17 @@ static inline int of_drm_get_panel_orientation(const struct device_node *np,
#if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
(IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
int drm_panel_of_backlight(struct drm_panel *panel);
+int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux);
#else
static inline int drm_panel_of_backlight(struct drm_panel *panel)
{
return 0;
}
+static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel,
+ struct drm_dp_aux *aux)
+{
+ return 0;
+}
#endif
#endif
--
2.7.4
Am 26.06.21 um 18:51 schrieb Rajeev Nandan:
> Some panels support backlight control over DP AUX channel using
> VESA's standard backlight control interface.
> Using new DRM eDP backlight helpers, add support to create and
> register a backlight for those panels in drm_panel to simplify
> the panel drivers.
>
> The panel driver with access to "struct drm_dp_aux" can create and
> register a backlight device using following code snippet in its
> probe() function:
>
> err = drm_panel_dp_aux_backlight(panel, aux);
> if (err)
> return err;
>
> Then drm_panel will handle backlight_(enable|disable) calls
> similar to the case when drm_panel_of_backlight() is used.
>
> Currently, we are not supporting one feature where the source
> device can combine the backlight brightness levels set through
> DP AUX and the BL_PWM_DIM eDP connector pin. Since it's not
> required for the basic backlight controls, it can be added later.
>
> Signed-off-by: Rajeev Nandan <[email protected]>
> Reviewed-by: Douglas Anderson <[email protected]>
> Reviewed-by: Lyude Paul <[email protected]>
> ---
>
> Changes in v5:
> - New
>
> Changes in v6:
> - Fixed ordering of memory allocation (Douglas)
> - Updated word wrapping in a comment (Douglas)
>
> Changes in v8:
> - Now using backlight_is_blank() to get the backlight blank status (Sam Ravnborg)
>
> drivers/gpu/drm/drm_panel.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
> include/drm/drm_panel.h | 15 ++++--
> 2 files changed, 119 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index f634371..4fa1e3b 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -26,12 +26,20 @@
> #include <linux/module.h>
>
> #include <drm/drm_crtc.h>
> +#include <drm/drm_dp_helper.h>
> #include <drm/drm_panel.h>
> #include <drm/drm_print.h>
>
> static DEFINE_MUTEX(panel_lock);
> static LIST_HEAD(panel_list);
>
> +struct dp_aux_backlight {
> + struct backlight_device *base;
> + struct drm_dp_aux *aux;
> + struct drm_edp_backlight_info info;
> + bool enabled;
> +};
> +
> /**
> * DOC: drm panel
> *
> @@ -342,6 +350,106 @@ int drm_panel_of_backlight(struct drm_panel *panel)
> return 0;
> }
> EXPORT_SYMBOL(drm_panel_of_backlight);
> +
> +static int dp_aux_backlight_update_status(struct backlight_device *bd)
> +{
> + struct dp_aux_backlight *bl = bl_get_data(bd);
> + u16 brightness = backlight_get_brightness(bd);
> + int ret = 0;
> +
> + if (!backlight_is_blank(bd)) {
> + if (!bl->enabled) {
> + drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
> + bl->enabled = true;
> + return 0;
> + }
> + ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness);
> + } else {
> + if (bl->enabled) {
> + drm_edp_backlight_disable(bl->aux, &bl->info);
> + bl->enabled = false;
> + }
> + }
> +
> + return ret;
> +}
> +
> +static const struct backlight_ops dp_aux_bl_ops = {
> + .update_status = dp_aux_backlight_update_status,
> +};
> +
> +/**
> + * drm_panel_dp_aux_backlight - create and use DP AUX backlight
> + * @panel: DRM panel
> + * @aux: The DP AUX channel to use
> + *
> + * Use this function to create and handle backlight if your panel
> + * supports backlight control over DP AUX channel using DPCD
> + * registers as per VESA's standard backlight control interface.
> + *
> + * When the panel is enabled backlight will be enabled after a
> + * successful call to &drm_panel_funcs.enable()
> + *
> + * When the panel is disabled backlight will be disabled before the
> + * call to &drm_panel_funcs.disable().
> + *
> + * A typical implementation for a panel driver supporting backlight
> + * control over DP AUX will call this function at probe time.
> + * Backlight will then be handled transparently without requiring
> + * any intervention from the driver.
> + *
> + * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init().
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux)
> +{
> + struct dp_aux_backlight *bl;
> + struct backlight_properties props = { 0 };
> + u16 current_level;
> + u8 current_mode;
> + u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
> + int ret;
> +
> + if (!panel || !panel->dev || !aux)
> + return -EINVAL;
> +
> + ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,
> + EDP_DISPLAY_CTL_CAP_SIZE);
This creates a cyclic dependency between drm_kms_helper-ko and drm.ko.
drm_panel.c is in the latter, while drm_dp_dpcd_read() in
drm_dp_helper.c is in the former. Please fix.
Best regards
Thomas
> + if (ret < 0)
> + return ret;
> +
> + if (!drm_edp_backlight_supported(edp_dpcd)) {
> + DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n");
> + return 0;
> + }
> +
> + bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL);
> + if (!bl)
> + return -ENOMEM;
> +
> + bl->aux = aux;
> +
> + ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd,
> + ¤t_level, ¤t_mode);
> + if (ret < 0)
> + return ret;
> +
> + props.type = BACKLIGHT_RAW;
> + props.brightness = current_level;
> + props.max_brightness = bl->info.max;
> +
> + bl->base = devm_backlight_device_register(panel->dev, "dp_aux_backlight",
> + panel->dev, bl,
> + &dp_aux_bl_ops, &props);
> + if (IS_ERR(bl->base))
> + return PTR_ERR(bl->base);
> +
> + panel->backlight = bl->base;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_panel_dp_aux_backlight);
> #endif
>
> MODULE_AUTHOR("Thierry Reding <[email protected]>");
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index 33605c3..3ebfaa6 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -32,6 +32,7 @@ struct backlight_device;
> struct device_node;
> struct drm_connector;
> struct drm_device;
> +struct drm_dp_aux;
> struct drm_panel;
> struct display_timing;
>
> @@ -64,8 +65,8 @@ enum drm_panel_orientation;
> * the panel. This is the job of the .unprepare() function.
> *
> * Backlight can be handled automatically if configured using
> - * drm_panel_of_backlight(). Then the driver does not need to implement the
> - * functionality to enable/disable backlight.
> + * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
> + * does not need to implement the functionality to enable/disable backlight.
> */
> struct drm_panel_funcs {
> /**
> @@ -144,8 +145,8 @@ struct drm_panel {
> * Backlight device, used to turn on backlight after the call
> * to enable(), and to turn off backlight before the call to
> * disable().
> - * backlight is set by drm_panel_of_backlight() and drivers
> - * shall not assign it.
> + * backlight is set by drm_panel_of_backlight() or
> + * drm_panel_dp_aux_backlight() and drivers shall not assign it.
> */
> struct backlight_device *backlight;
>
> @@ -208,11 +209,17 @@ static inline int of_drm_get_panel_orientation(const struct device_node *np,
> #if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
> (IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
> int drm_panel_of_backlight(struct drm_panel *panel);
> +int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux);
> #else
> static inline int drm_panel_of_backlight(struct drm_panel *panel)
> {
> return 0;
> }
> +static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel,
> + struct drm_dp_aux *aux)
> +{
> + return 0;
> +}
> #endif
>
> #endif
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
Hi
Am 12.07.21 um 11:41 schrieb Thomas Zimmermann:
>
>
> Am 26.06.21 um 18:51 schrieb Rajeev Nandan:
>> Some panels support backlight control over DP AUX channel using
>> VESA's standard backlight control interface.
>> Using new DRM eDP backlight helpers, add support to create and
>> register a backlight for those panels in drm_panel to simplify
>> the panel drivers.
>>
>> The panel driver with access to "struct drm_dp_aux" can create and
>> register a backlight device using following code snippet in its
>> probe() function:
>>
>> err = drm_panel_dp_aux_backlight(panel, aux);
>> if (err)
>> return err;
>>
>> Then drm_panel will handle backlight_(enable|disable) calls
>> similar to the case when drm_panel_of_backlight() is used.
>>
>> Currently, we are not supporting one feature where the source
>> device can combine the backlight brightness levels set through
>> DP AUX and the BL_PWM_DIM eDP connector pin. Since it's not
>> required for the basic backlight controls, it can be added later.
>>
>> Signed-off-by: Rajeev Nandan <[email protected]>
>> Reviewed-by: Douglas Anderson <[email protected]>
>> Reviewed-by: Lyude Paul <[email protected]>
>> ---
>>
>> Changes in v5:
>> - New
>>
>> Changes in v6:
>> - Fixed ordering of memory allocation (Douglas)
>> - Updated word wrapping in a comment (Douglas)
>>
>> Changes in v8:
>> - Now using backlight_is_blank() to get the backlight blank status
>> (Sam Ravnborg)
>>
>> drivers/gpu/drm/drm_panel.c | 108
>> ++++++++++++++++++++++++++++++++++++++++++++
>> include/drm/drm_panel.h | 15 ++++--
>> 2 files changed, 119 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
>> index f634371..4fa1e3b 100644
>> --- a/drivers/gpu/drm/drm_panel.c
>> +++ b/drivers/gpu/drm/drm_panel.c
>> @@ -26,12 +26,20 @@
>> #include <linux/module.h>
>> #include <drm/drm_crtc.h>
>> +#include <drm/drm_dp_helper.h>
>> #include <drm/drm_panel.h>
>> #include <drm/drm_print.h>
>> static DEFINE_MUTEX(panel_lock);
>> static LIST_HEAD(panel_list);
>> +struct dp_aux_backlight {
>> + struct backlight_device *base;
>> + struct drm_dp_aux *aux;
>> + struct drm_edp_backlight_info info;
>> + bool enabled;
>> +};
>> +
>> /**
>> * DOC: drm panel
>> *
>> @@ -342,6 +350,106 @@ int drm_panel_of_backlight(struct drm_panel *panel)
>> return 0;
>> }
>> EXPORT_SYMBOL(drm_panel_of_backlight);
>> +
>> +static int dp_aux_backlight_update_status(struct backlight_device *bd)
>> +{
>> + struct dp_aux_backlight *bl = bl_get_data(bd);
>> + u16 brightness = backlight_get_brightness(bd);
>> + int ret = 0;
>> +
>> + if (!backlight_is_blank(bd)) {
>> + if (!bl->enabled) {
>> + drm_edp_backlight_enable(bl->aux, &bl->info, brightness);
>> + bl->enabled = true;
>> + return 0;
>> + }
>> + ret = drm_edp_backlight_set_level(bl->aux, &bl->info,
>> brightness);
>> + } else {
>> + if (bl->enabled) {
>> + drm_edp_backlight_disable(bl->aux, &bl->info);
>> + bl->enabled = false;
>> + }
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static const struct backlight_ops dp_aux_bl_ops = {
>> + .update_status = dp_aux_backlight_update_status,
>> +};
>> +
>> +/**
>> + * drm_panel_dp_aux_backlight - create and use DP AUX backlight
>> + * @panel: DRM panel
>> + * @aux: The DP AUX channel to use
>> + *
>> + * Use this function to create and handle backlight if your panel
>> + * supports backlight control over DP AUX channel using DPCD
>> + * registers as per VESA's standard backlight control interface.
>> + *
>> + * When the panel is enabled backlight will be enabled after a
>> + * successful call to &drm_panel_funcs.enable()
>> + *
>> + * When the panel is disabled backlight will be disabled before the
>> + * call to &drm_panel_funcs.disable().
>> + *
>> + * A typical implementation for a panel driver supporting backlight
>> + * control over DP AUX will call this function at probe time.
>> + * Backlight will then be handled transparently without requiring
>> + * any intervention from the driver.
>> + *
>> + * drm_panel_dp_aux_backlight() must be called after the call to
>> drm_panel_init().
>> + *
>> + * Return: 0 on success or a negative error code on failure.
>> + */
>> +int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct
>> drm_dp_aux *aux)
>> +{
>> + struct dp_aux_backlight *bl;
>> + struct backlight_properties props = { 0 };
>> + u16 current_level;
>> + u8 current_mode;
>> + u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
>> + int ret;
>> +
>> + if (!panel || !panel->dev || !aux)
>> + return -EINVAL;
>> +
>> + ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,
>> + EDP_DISPLAY_CTL_CAP_SIZE);
>
> This creates a cyclic dependency between drm_kms_helper-ko and drm.ko.
> drm_panel.c is in the latter, while drm_dp_dpcd_read() in
> drm_dp_helper.c is in the former. Please fix.
FYI, build DRM as modules and the error shows up during make module_install.
Best regards
Thomas
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
Hi,
On Mon, Jul 12, 2021 at 2:41 AM Thomas Zimmermann <[email protected]> wrote:
>
> > + ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,
> > + EDP_DISPLAY_CTL_CAP_SIZE);
>
> This creates a cyclic dependency between drm_kms_helper-ko and drm.ko.
> drm_panel.c is in the latter, while drm_dp_dpcd_read() in
> drm_dp_helper.c is in the former. Please fix.
Yeah, this was reported Friday and I posted a patch to try to fix it:
https://lore.kernel.org/lkml/20210709152909.1.I23eb4cc5a680341e7b3e791632a635566fa5806a@changeid/
I see Rajeev had some feedback on it. Once I've dug out of my weekend
email hole I'll take a look at plan to post a v2 ASAP.
-Doug
Hi,
On Mon, Jul 12, 2021 at 6:39 AM Doug Anderson <[email protected]> wrote:
>
> Hi,
>
> On Mon, Jul 12, 2021 at 2:41 AM Thomas Zimmermann <[email protected]> wrote:
> >
> > > + ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd,
> > > + EDP_DISPLAY_CTL_CAP_SIZE);
> >
> > This creates a cyclic dependency between drm_kms_helper-ko and drm.ko.
> > drm_panel.c is in the latter, while drm_dp_dpcd_read() in
> > drm_dp_helper.c is in the former. Please fix.
>
> Yeah, this was reported Friday and I posted a patch to try to fix it:
>
> https://lore.kernel.org/lkml/20210709152909.1.I23eb4cc5a680341e7b3e791632a635566fa5806a@changeid/
>
> I see Rajeev had some feedback on it. Once I've dug out of my weekend
> email hole I'll take a look at plan to post a v2 ASAP.
Breadcrumbs: v2 of the fix is at:
https://lore.kernel.org/lkml/20210712075933.v2.1.I23eb4cc5a680341e7b3e791632a635566fa5806a@changeid/
I'm hoping this looks OK so we can get this resolved before it trips
too many people up.
-Doug