Tag Archives: sd8787

Tablet guts

Tablet gutsIn case you want to know what the inside of a Samsung Galaxy Tab 3.0 looks like, I propose the following experiment: unplug one, and let it sit unused and un-powered for two months. You will then find it in the state where disconnecting and reconnecting the battery is required to get it to charge again. I am not making this up. Oh, and opening it is pretty tricky even with the proper plastic tools to do so. Since I have two of them, that’s how I lost thirty minutes of my life on Saturday.

As for why I have two: this particular model has a Marvell SoC inside, and the wireless SD8787 peripheral can be used with the upstream cfg80211-based mwifiex driver. For cozybit, I helped write an alternative mac80211 driver that can run mesh. It was a little slower and more power hungry than mwifiex, but in addition to being mesh/ibss/AP capable, had some nice-for-development features like SDIO tracing and an nl80211-testmode interface that could run firmware commands from userspace, upon which we built some test scaffolding. You can get the code for that driver today, but development is pretty much at a dead end because we needed to extend the firmware for host-based operation, and there will probably never be a redistributable firmware at this point.

I’d love to have an open firmware for the device, but as I have seen and touched the NDA encumbered firmware, it’s unlikely that I can have any hand in bringing that about.