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-rw-r--r--Documentation/firmware_class/README12
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/firmware_class/README b/Documentation/firmware_class/README
index 815b711bcd85..43fada989e65 100644
--- a/Documentation/firmware_class/README
+++ b/Documentation/firmware_class/README
@@ -22,12 +22,17 @@
22 - calls request_firmware(&fw_entry, $FIRMWARE, device) 22 - calls request_firmware(&fw_entry, $FIRMWARE, device)
23 - kernel searchs the fimware image with name $FIRMWARE directly 23 - kernel searchs the fimware image with name $FIRMWARE directly
24 in the below search path of root filesystem: 24 in the below search path of root filesystem:
25 User customized search path by module parameter 'path'[1]
25 "/lib/firmware/updates/" UTS_RELEASE, 26 "/lib/firmware/updates/" UTS_RELEASE,
26 "/lib/firmware/updates", 27 "/lib/firmware/updates",
27 "/lib/firmware/" UTS_RELEASE, 28 "/lib/firmware/" UTS_RELEASE,
28 "/lib/firmware" 29 "/lib/firmware"
29 - If found, goto 7), else goto 2) 30 - If found, goto 7), else goto 2)
30 31
32 [1], the 'path' is a string parameter which length should be less
33 than 256, user should pass 'firmware_class.path=$CUSTOMIZED_PATH'
34 if firmware_class is built in kernel(the general situation)
35
31 2), userspace: 36 2), userspace:
32 - /sys/class/firmware/xxx/{loading,data} appear. 37 - /sys/class/firmware/xxx/{loading,data} appear.
33 - hotplug gets called with a firmware identifier in $FIRMWARE 38 - hotplug gets called with a firmware identifier in $FIRMWARE
@@ -114,3 +119,10 @@
114 on the setup, so I think that the choice on what firmware to make 119 on the setup, so I think that the choice on what firmware to make
115 persistent should be left to userspace. 120 persistent should be left to userspace.
116 121
122 about firmware cache:
123 --------------------
124 After firmware cache mechanism is introduced during system sleep,
125 request_firmware can be called safely inside device's suspend and
126 resume callback, and callers need't cache the firmware by
127 themselves any more for dealing with firmware loss during system
128 resume.