Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux...

[firefly-linux-kernel-4.4.55.git] / Documentation / firmware_class / README

diff --git a/Documentation/firmware_class/README b/Documentation/firmware_class/README
index 815b711bcd85007569918048b2d3e36fe20fea19..43fada989e65f2b27111c1b3fb7190ef81092014 100644 (file)
--- a/Documentation/firmware_class/README
+++ b/Documentation/firmware_class/README
@@ -22,12 +22,17 @@
        - calls request_firmware(&fw_entry, $FIRMWARE, device)
        - kernel searchs the fimware image with name $FIRMWARE directly
        in the below search path of root filesystem:
+               User customized search path by module parameter 'path'[1]
                "/lib/firmware/updates/" UTS_RELEASE,
                "/lib/firmware/updates",
                "/lib/firmware/" UTS_RELEASE,
                "/lib/firmware"
        - If found, goto 7), else goto 2)
 
+       [1], the 'path' is a string parameter which length should be less
+       than 256, user should pass 'firmware_class.path=$CUSTOMIZED_PATH'
+       if firmware_class is built in kernel(the general situation)
+
  2), userspace:
        - /sys/class/firmware/xxx/{loading,data} appear.
        - hotplug gets called with a firmware identifier in $FIRMWARE
@@ -114,3 +119,10 @@
    on the setup, so I think that the choice on what firmware to make
    persistent should be left to userspace.
 
+ about firmware cache:
+ --------------------
+ After firmware cache mechanism is introduced during system sleep,
+ request_firmware can be called safely inside device's suspend and
+ resume callback, and callers need't cache the firmware by
+ themselves any more for dealing with firmware loss during system
+ resume.