Thursday, February 28, 2013

AnandTech Article Channel

AnandTech Article Channel

OpenCL drivers discovered on Nexus 4 and Nexus 10 devices

Posted: 27 Feb 2013 07:07 AM PST

As regular Anandtech readers will know, OpenCL is a standard by Khronos group that allows you to access the computational power of parallel devices such as multicore CPUs and GPUs in your system provided the hardware and drivers support the API. Companies such as AMD, Intel and Nvidia have been shipping OpenCL drivers on the desktop for some time now. On the mobile side, vendors such as ARM,  Imagination, Qualcomm, Samsung and TI have been promising OpenCL on mobile and often show off demos using OpenCL. Drivers from vendors such as ARM, Qualcomm and Imagination have also passed official conformance tests, certifying that they do have working drivers in at least development firmwares. However,  none of the vendors have publically announced whether or not they are already shipping OpenCL in stock firmware on any device. ARM and Qualcomm have both maintained that licensing and shipping the OpenCL driver is upto the handset makers and have not issued any documentation confirming which handsets or tablets do ship with OpenCL. Google has also always maintained that Renderscript Compute, and not OpenCL, is the official parallel computing API for Android.

However, recently we have seen several stories that OpenCL drivers are in fact present on both Nexus 4 and Nexus 10 stock firmware. I first became aware of the presence of OpenCL for Mali T604 on Nexus 10 stock firmware through a tweet from Kishonti who were able to run their CLBenchmark test on the Nexus 10. Then, posters on several forums (such as bearon on Beyond3D forum ) posted instructions on how to get access to OpenCL on Nexus 10. Matthew Scarpino has also posted some instructions for Nexus 10 on his blog . Finally, posters on Qualcomm developer forums posted that Nexus 4 also appears to ship with OpenCL drivers, and gave some instructions on how to get access to OpenCL on Nexus 4. On Nexus 4, drivers appear to be present for both the quad-core Krait CPU and Adreno 320 GPU.

We have also been able to confirm ourselves that both Nexus 4 and Nexus 10 contain OpenCL drivers, though we have only tested very basic functions in the API so far. I have posted sample code here that appears to be working on both Nexus 4 and Nexus 10 and does not require you to pull any proprietary binaries from the firmware, unlike some other proposed solutions. I will keep updating the source code over time as I learn more.

It is not clear whether the shipping drivers are the conformant drivers referred to above, or some other internal build that may not have the full functionality of the API.  It is potentially risky for commercial apps to depend upon the libraries, as they may be buggy or unstable, and may also disappear in future firmware versions. However, it is still an exciting development for developers and tinkerers, as it opens up the way for developers to explore the potential of OpenCL on mobile/low-power platforms.


A Look at Broadcom's BCM21892 LTE Baseband at MWC

Posted: 26 Feb 2013 11:42 PM PST

Yesterday we stopped by Broadcom to look at their newly announced BCM21892 LTE baseband, which we saw teased previously at CES doing a VoLTE call. If you're not famliar with the details of Broadcom's first LTE baseband, it's a 3GPP Release 10 modem supporting all the 3GPP air interfaces (GSM/EDGE, WCDMA, TD-SCDMA, LTE) with Category 4 LTE support, support for 10+10 MHz carrier aggregation, integrated 8 port transceiver into the baseband package, and built on a 28nm HPm process.

Broadcom's LTE Baseband
3GPP Release Rel. 10 (LTE-A)
HSPA+ Category Cat. 24, DC-HSPA+ 42.2 Mbps
LTE Cat. 4, LTE-A 150 Mbps Downlink / 50 Mbps Uplink
2x2 MIMO
Voice VoLTE, CS WCDMA/GSM voice
Process 28nm HPm
Package Plastic(?) with integrated DRAM and 8-port Transceiver
Extra External PMIC, "35% smaller required implementation area," envelope tracking supported

There's nothing new about the feature set, but it was nice to see BCM21892 silicon working and demonstrating all of the available features we heard about in the announcement working. I recorded a video of the entire demo walkthrough which I'd encourage you to watch if you're interested. The booth contained both BCM21892 working on a few demo boards, as well as integrated with their own platform form factor reference design which runs the full house of Broadcom silicon - WLAN/BT Combo, SoC, and GPS. 

Broadcom demonstrated both full 150 Mbps UE Category 4 rates on a cabled up demo, 10 + 10 MHz carrier aggregation on Band 17 and 4 (AT&T's configuration) switching in and out the band 4 carrier, and envelope tracking support working on the BCM21892. 

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