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greybus: svc: reconfig APBridgeA-Switch link to handle required load

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SW-4894, SW-4389, and share a common root cause, namely that
the power-on reset configuration of the APBridgeA-Switch link of PWM
Gear 1, 1 Lane, Slow Auto, is insufficient to handle some required
traffic loads, such as 3 audio streams plus boot-over-UniPro or 4 audio
streams.

The correct long-term solution is to implement a UniPro Power Mode
Manager as in that considers the demands placed on the network,
and adjusts power modes accordingly.

The present commit implements a short-term, brute-force hack to allow
continued system testing:
- Upon receiving an SVC HELLO request, schedule deferred work to
  reconfigure the APB1-Switch link to PWM G2, 1 lane, Slow Auto
- When the Camera driver transitions a White Camera module from active to
  inactive, return the APB1-Switch link to PWM G2, 1 lane, Slow Auto

The Camera driver already steps up the APBridgeA-Camera link speed while a
camera module is active, which affords sufficient margin for simultaneous
audio and hotplug activity, and the Camera driver already steps down the
link speed thereafter: the change made by the present patch is simply to
tweak the stepped-down power mode to match the new baseline configuration.

Signed-off-by: Mitchell Tasman <tasman@leaflabs.com>
Tested-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Mitchell Tasman 2016-05-04 17:30:23 -04:00 committed by Greg Kroah-Hartman
parent 3e29bcf4b1
commit ee2f2074fd
2 changed files with 37 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/staging/greybus/camera.c
View file

@ -131,9 +131,9 @@ static int gb_camera_set_intf_power_mode(struct gb_camera *gcam, u8 intf_id,
ret = gb_svc_intf_set_power_mode(svc, intf_id,
GB_SVC_UNIPRO_HS_SERIES_A,
GB_SVC_UNIPRO_SLOW_AUTO_MODE,
1, 2,
2, 1,
GB_SVC_UNIPRO_SLOW_AUTO_MODE,
1, 2,
2, 1,
0, 0);
return ret;

36
drivers/staging/greybus/svc.c
View file

@ -23,6 +23,8 @@ struct gb_svc_deferred_request {
};
static int gb_svc_queue_deferred_request(struct gb_operation *operation);
static ssize_t endo_id_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -695,7 +697,7 @@ static int gb_svc_hello(struct gb_operation *op)
gb_svc_debugfs_init(svc);
return 0;
return gb_svc_queue_deferred_request(op);
}
static struct gb_interface *gb_svc_interface_lookup(struct gb_svc *svc,
@ -754,6 +756,35 @@ static void gb_svc_intf_reenable(struct gb_svc *svc, struct gb_interface *intf)
mutex_unlock(&intf->mutex);
}
static void gb_svc_process_hello_deferred(struct gb_operation *operation)
{
struct gb_connection *connection = operation->connection;
struct gb_svc *svc = gb_connection_get_data(connection);
int ret;
/*
* XXX This is a hack/work-around to reconfigure the APBridgeA-Switch
* link to PWM G2, 1 Lane, Slow Auto, so that it has sufficient
* bandwidth for 3 audio streams plus boot-over-UniPro of a hot-plugged
* module.
*
* The code should be removed once SW-2217, Heuristic for UniPro
* Power Mode Changes is resolved.
*/
ret = gb_svc_intf_set_power_mode(svc, svc->ap_intf_id,
GB_SVC_UNIPRO_HS_SERIES_A,
GB_SVC_UNIPRO_SLOW_AUTO_MODE,
2, 1,
GB_SVC_UNIPRO_SLOW_AUTO_MODE,
2, 1,
0, 0);
if (ret)
dev_warn(&svc->dev,
"power mode change failed on AP to switch link: %d\n",
ret);
}
static void gb_svc_process_intf_hotplug(struct gb_operation *operation)
{
struct gb_svc_intf_hotplug_request *request;
@ -963,6 +994,9 @@ static void gb_svc_process_deferred_request(struct work_struct *work)
type = operation->request->header->type;
switch (type) {
case GB_SVC_TYPE_SVC_HELLO:
gb_svc_process_hello_deferred(operation);
break;
case GB_SVC_TYPE_INTF_HOTPLUG:
gb_svc_process_intf_hotplug(operation);
break;