[Bluez-devel] how well supported is hci_read_rssi and hci_read_link_quality?

[Bluez-devel] how well supported is hci_read_rssi and hci_read_link_quality?

[Albert Huang]

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Hello,

Does anyone have a rough estimate, or even a list, of the devices that
support hci_read_rssi and hci_read_link_quality?  Am I correct in
assuming that some devices supoprt it and some don't?  For example, a
program that reads rssi and link quality that works beautifully on an
x86 with a d-link usb bluetooth dongle doesn't seem to work at all on
an HP ipaq h5550.  On the ipaq, the link quality is always 0 and rssi
is always 255.

The attached patch changes cmd_lq in hcitool.c to print out an
unsigned integer instead of a signed integer.

thanks.
-albert

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Index: tools/hcitool.c
===================================================================
RCS file: /cvsroot/bluez/utils/tools/hcitool.c,v
retrieving revision 1.44
diff -u -r1.44 hcitool.c
--- tools/hcitool.c	12 Jun 2004 09:41:17 -0000	1.44
+++ tools/hcitool.c	23 Jun 2004 05:17:27 -0000
@@ -982,7 +982,7 @@
 				rp.status);
 		exit(1);
 	}
-	printf("Link quality: %d\n", rp.link_quality);
+	printf("Link quality: %u\n", rp.link_quality);
 
 	close(dd);
 	free(cr);

Re: [Bluez-devel] how well supported is hci_read_rssi and hci_read_link_quality?

[Marcel Holtmann]

Hi Albert,

> Does anyone have a rough estimate, or even a list, of the devices that
> support hci_read_rssi and hci_read_link_quality?  Am I correct in
> assuming that some devices supoprt it and some don't?  For example, a
> program that reads rssi and link quality that works beautifully on an
> x86 with a d-link usb bluetooth dongle doesn't seem to work at all on
> an HP ipaq h5550.  On the ipaq, the link quality is always 0 and rssi
> is always 255.

the link quality command is vendor specific, so you can't rely on it. We
only know how CSR uses it. The RSSI must be announced in the features
bits.

> The attached patch changes cmd_lq in hcitool.c to print out an
> unsigned integer instead of a signed integer.

Does this make any difference? The link quality is only uint8.

Regards

Marcel




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Re: Re: [Bluez-devel] how well supported is hci_read_rssi and hci_read_link_quality?

[Albert Huang]

> Does this make any difference? The link quality is only uint8.

hmm... yes, I don't know what got into me that late in the night.  I
guess I was seeing negative numbers for rssi and thought gee, link
quality shouldn't be negative.  A useless, but harmless patch.

-albert