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authorBenjamin Tissoires <benjamin.tissoires@redhat.com>2017-03-08 17:11:14 +0300
committerJiri Kosina <jkosina@suse.cz>2017-03-21 16:59:56 +0300
commit9143059fafd4eebed2d43ffb5455178d4010e60a (patch)
tree58710b0bd2717dea4c871740bcd95c436ae53db0 /include/linux/hid.h
parent81bbef23db51c0b450d90607fbbc2ad80ee0d43f (diff)
downloadlinux-9143059fafd4eebed2d43ffb5455178d4010e60a.tar.xz
HID: remove initial reading of reports at connect
It looks like a bunch of devices do not like to be polled for their reports at init time. When you look into the details, it seems that for those that are requiring the quirk HID_QUIRK_NO_INIT_REPORTS, the driver fails to retrieve part of the features/inputs while others (more generic) work. IMO, it should be acceptable to remove the need for the quirk in the general case. On the small amount of cases where we actually need to read the current values, the driver in charge (hid-mt or wacom) already retrieves the features manually. There are 2 cases where we might need to retrieve the reports at init: 1. hiddev devices with specific use-space tool 2. a device that would require the driver to fetch a specific feature/input at plug For case 2, I have seen this a few time on hid-multitouch. It is solved in hid-multitouch directly by fetching the feature. I hope it won't be too common and this can be solved on a per-case basis (crossing fingers). For case 1, we moved the implementation of HID_QUIRK_NO_INIT_REPORTS in hiddev. When somebody starts calling ioctls that needs an initial update, the hiddev device will fetch the initial state of the reports to mimic the current behavior. This adds a small amount of time during the first HIDIOCGUSAGE(S), but it should be acceptable in most cases. To keep the currently known broken devices, we have to keep around HID_QUIRK_NO_INIT_REPORTS, but the scope will only be for hiddev. Note that I don't think hidraw would be affected and I checked that the FF drivers that need to interact with the report fields are all using output reports, which are not initialized by usbhid_init_reports(). NO_INIT_INPUT_REPORTS is then replaced by HID_QUIRK_NO_INIT_REPORTS: there is no point keeping it for just one device. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'include/linux/hid.h')
-rw-r--r--include/linux/hid.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 28f38e2b8f30..b2e472c3e595 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -322,7 +322,7 @@ struct hid_item {
#define HID_QUIRK_MULTI_INPUT 0x00000040
#define HID_QUIRK_HIDINPUT_FORCE 0x00000080
#define HID_QUIRK_NO_EMPTY_INPUT 0x00000100
-#define HID_QUIRK_NO_INIT_INPUT_REPORTS 0x00000200
+/* 0x00000200 reserved for backward compatibility, was NO_INIT_INPUT_REPORTS */
#define HID_QUIRK_ALWAYS_POLL 0x00000400
#define HID_QUIRK_SKIP_OUTPUT_REPORTS 0x00010000
#define HID_QUIRK_SKIP_OUTPUT_REPORT_ID 0x00020000