Simple but effective way of chaging HID device descriptors
RFC 1/1 Simple but effective way of chaging HID device descriptors
Simple but effective way of chaging HID device descriptorsusing firmware loading mechanism. Just place your new descriptor in a location specified by driver
i.e. somewhere in /lib/firmware/hid/
If it is there it will replace HID descriptor from the device.
I do not do any parsing or checking, as it is done by hid driver.
Signed-off-by Marcin Tolysz <[email protected]>
--- drivers/hid/hid-core.c | 26 +++++++++++++++++++++++++- 1 files changed, 25 insertions(+), 1 deletions(-)
drivers/hid/hid-core.c +25 -1
@@ -27,6 +27,7 @@#include <linux/wait.h> #include <linux/vmalloc.h> #include <linux/sched.h> +#include <linux/firmware.h> #include <linux/hid.h> #include <linux/hiddev.h>
@@ -640,6 +641,10 @@ int hid_parse_report(struct hid_device *device, __u8 *start,struct hid_item item;__u8 *end;int ret; +const struct firmware *fw; +int succ; +char *file; +static int (*dispatch_type[])(struct hid_parser *parser,struct hid_item *item) = { hid_parser_main,
@@ -650,10 +655,27 @@ int hid_parse_report(struct hid_device *device, __u8 *start,if (device->driver->report_fixup) device->driver->report_fixup (device, start, size); +/* Now load a hid descriptor from a file firmware +ignoring this fixup thing */ + file=kmalloc (29 ,GFP_KERNEL ); +sprintf (file,"hid/%04X:%04X:%04X:%04X.bin" ,device->bus,device->vendor,device->product,device->version); + + succ =request_firmware (&fw, file, &device->dev); + +if (succ) +printk (KERN_INFO "To relace HID descriptor place it in /lib/firmaware/%s\n" , file); +else { + start = fw->data; + size = fw->size; +printk (KERN_INFO "HID descriptor relaced with /lib/firmaware/%s\n" , file); + } +kfree (file); device->rdesc =kmalloc (size,GFP_KERNEL ); -if (device->rdesc ==NULL ) +if (device->rdesc ==NULL ){ +if (!succ)release_firmware (fw);return -ENOMEM ; + }memcpy (device->rdesc, start, size); device->rsize = size;
@@ -690,6 +712,7 @@ int hid_parse_report(struct hid_device *device, __u8 *start,dbg_hid ("unbalanced delimiter at end of report description\n" ); goto err; } +if (!succ)release_firmware (fw);vfree (parser);return 0 ; }
@@ -697,6 +720,7 @@ int hid_parse_report(struct hid_device *device, __u8 *start,dbg_hid ("item fetching failed at offset %d\n" , (int )(end - start)); err: +if (!succ)release_firmware (fw);vfree (parser);return ret; }
-- 1.6.5.7