25-03-2021

Drivers QCI

Quality Carriers, Inc. (QCI), is one of the largest chemical bulk transportation companies in North America. We have the industry's most extensive and complete terminal network with the largest.

  1. Drivers Quizzes
  2. Drivers Circle

Powered by A tiny 6mm driver sits inside the headphones to deliver clear sound. Bluetooth 5.0 deliver a faster and more stable wireless connection to your devices. The chip also drives voice-enabled assistant access and delivers up to 65 percent lower gaming latency. Contact Quality Carriers 1208 East Kennedy Boulevard Suite 132 Tampa, FL 33602 (800) 282-2031.

Drivers

Author: Robert Jarzmik <robert.jarzmik@free.fr>

24.1. Constraints¶

  1. Image size for YUV422P formatAll YUV422P images are enforced to have width x height % 16 = 0.This is due to DMA constraints, which transfers only planes of 8 bytemultiples.

24.2. Global video workflow¶

  1. QCI stoppedInitialy, the QCI interface is stopped.When a buffer is queued (pxa_videobuf_ops->buf_queue), the QCI starts.

  2. QCI startedMore buffers can be queued while the QCI is started without halting thecapture. The new buffers are “appended” at the tail of the DMA chain, andsmoothly captured one frame after the other.

    Once a buffer is filled in the QCI interface, it is marked as “DONE” andremoved from the active buffers list. It can be then requeud or dequeued byuserland application.

    Once the last buffer is filled in, the QCI interface stops.

  3. Capture global finite state machine schema

Drivers Quizzes

24.3. DMA usage¶

  1. DMA flow
    • first buffer queued for captureOnce a first buffer is queued for capture, the QCI is started, but datatransfer is not started. On “End Of Frame” interrupt, the irq handlerstarts the DMA chain.
    • capture of one videobufferThe DMA chain starts transferring data into videobuffer RAM pages.When all pages are transferred, the DMA irq is raised on “ENDINTR” status
    • finishing one videobufferThe DMA irq handler marks the videobuffer as “done”, and removes it fromthe active running queueMeanwhile, the next videobuffer (if there is one), is transferred by DMA
    • finishing the last videobufferOn the DMA irq of the last videobuffer, the QCI is stopped.
  2. DMA prepared buffer will have this structure

This structure is pointed by dma->sg_cpu.The descriptors are used as follows:

  • desc-sg[i]: i-th descriptor, transferring the i-th sgelement to the video buffer scatter gather
  • finisher: has ddadr=DADDR_STOP, dcmd=ENDIRQEN
  • linker: has ddadr= desc-sg[0] of next video buffer, dcmd=0

For the next schema, let’s assume d0=desc-sg[0] .. dN=desc-sg[N],“f” stands for finisher and “l” for linker.A typical running chain is :

After the chaining is finished, the chain looks like :

Drivers Circle

  1. DMA hot chaining timeslice issue

As DMA chaining is done while DMA _is_ running, the linking may be donewhile the DMA jumps from one Videobuffer to another. On the schema, thatwould be a problem if the following sequence is encountered :

  • DMA chain is Videobuffer1 + Videobuffer2
  • pxa_videobuf_queue() is called to queue Videobuffer3
  • DMA controller finishes Videobuffer2, and DMA stops
  • pxa_dma_add_tail_buf() is called, the Videobuffer2 “finisher” isreplaced by a “linker” to Videobuffer3 (creation of new_link)
  • pxa_videobuf_queue() finishes
  • the DMA irq handler is called, which terminates Videobuffer2
  • Videobuffer3 capture is not scheduled on DMA chain (as it stopped !!!)
  • pxa_camera_check_link_miss() is calledThis checks if the DMA is finished and a buffer is still on thepcdev->capture list. If that’s the case, the capture will be restarted,and Videobuffer3 is scheduled on DMA chain.
  • the DMA irq handler finishes

Note

If DMA stops just after pxa_camera_check_link_miss() reads DDADR()value, we have the guarantee that the DMA irq handler will be called backwhen the DMA will finish the buffer, and pxa_camera_check_link_miss() willbe called again, to reschedule Videobuffer3.

  • About Quanta
    Company ProfileExecutivesOrganization StructureCompany InformationKey Milestone
  • Investor Relations
    FinancialsAnnual ReportsShareholders ServicesShareholders' Meeting
  • CSR
    CSR Committee’s structureStatement of CSR PolicyVision & MissionCSR reports
  • Products
  • Subsidiaries/Affiliates
    QSMCQCTQuanta Storage Inc.RoyalTek International Quanta Culture & Education FoundationQuanta Arts FoundationPILOT

Server

  • Founded in 2000, Quanta's Enterprise Solutions Business Unit (ESBU) was an innovator which focused on ODM/OEM business development and manufacturing of high-performance IT equipment, enabling enterprises to manage IT more effectively, to enhance business more efficiently and as a result, to get more profits eventually. Product lines include high level blade servers, 1U/2U/4U rack servers, server motherboards, 10GbE LAN cards, storage, and L2/L3 networking switches…etc. In recent years, cloud computing has become the market trend in the world. Therefore, ESBU was renamed to be Cloud Computing Business Unit (CCBU) in 2010.
  • CCBU has more than 600 experienced engineers dedicated for product development. By leveraging Quanta's strong manufacturing infrastructure, worldwide logistics, service centers, and supply chain, CCBU has successfully customized datacenter hardware solutions for international firms, telecom companies, and cloud service providers worldwide and is getting good prestige in the cloud industry.
  • In addition, CCBU is also devoted to provide green solutions from product design, customization, manufacturing, to stack & rack integration for your existing datacenter architecture and applications. Our vision is to build a partnership with our clients while developing high-performance, environmental-friendly system for corporate responsibility to our earth.
Unsurpassed 4U rackmount server for HPC & server consolidation
  • The Quanta 4U quad-processor rackmount server is designed to deliver high performance, reliability and scalability to enterprises with support for up to four multi-core Intel® Xeon® Processor 7500 series and large memory capacity in 64 DIMM slots. The expansion capacity makes it competitive and ideal for large-data-set workloads, business-critical applications (ERP, CRM, SAP…etc.), server virtualization & consolidation, and virtual desktop hosting. With the future-ready 4U server, there is no need to reconstruct data centers when enterprises want to increase workload capacity.
Impressively outstanding 1U/2U rackmount servers
  • Quanta 1U/2U servers provide business comprehensive system solutions by supporting the latest Intel® Xeon® multi-core processor 5500/5600 sequence and IPMI 2.0. In order to satisfy business' needs on remote management to the system, the server has 'KVM over IP' function. These 1U/2U new value-added servers are designed for increasing business' demands on HPC application, web-hosting infrastructure, front-end enterprise databases, minimal-downtime cluster server, and etc.
Large datacenter networking switches
  • Designed for the needs of enterprises and data centers, Quanta provides high quality and cost effective wire-speed layer2/3 switch products. In order to perfectly meet your evolving business requirements and new application deployments, Quanta delivers a wide range of products from 10 Gigabit to Fast Ethernet and provides options of open-source customization.
High density JBOD Storage
  • Flexible, affordable and highly available, Quanta storage enclosures integrate with Quanta servers to provide enterprises simple and affordable IT infrastructure. The 4U disk enclosure is designed to meet the needs of data growth and flexibility. Users could easily scale up the storage capability with the growth of their business, and access to critical data with high reliability because of the design of fully redundant controller modules, power supplies, hard disks, and cooling modules.
Integrated rack solution
  • Featuring centralized power and cooling system, the integrated rack solution is an optimized green modular design for different datacenter infrastructure, computing/storage density requirement, power efficiency, best PUE, and CAPEX/OPEX reduction.