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Subject: Re: [PATCH v2 11/16] Bluetooth: Add 'eir_len' param to
 mgmt_device_found()
From: Marcel Holtmann <marcel@holtmann.org>
To: Anderson Lizardo <anderson.lizardo@openbossa.org>
Cc: Andre Guedes <andre.guedes@openbossa.org>,
	linux-bluetooth@vger.kernel.org
Date: Wed, 10 Aug 2011 17:26:57 -0700
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Hi Anderson,

> > The advertising report event has the 'Length' field to inform the
> > 'Data' field length, so I believe it has a variable length.
> > According to its description, the 'Length' field may vary from 0x00
> > to 0x1F (31) bytes.
> 
> You are right. Although the section 11 gives the impression the size
> is always 31, this is not what happens on actual hardware, which
> usually sends only the significant bytes (and the length is know from
> the "Length" field.
> 
> > The only drawback I see so far is copying extra ~200 bytes each time
> > we get a advertising report data.
> 
> I agree. If this event is being sent on each adv. data report event,
> it will be more than 6 times the amount of data (with non-significant
> bytes containing only zeroes) sent to userspace.

if we wanna save bytes copied and send to userspace, then we might even
fix this for BR/EDR. Since while it is fixed there only a fraction is
used there most of the times.

Regards

Marcel