lkml.org 
[lkml]   [2012]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 1/2] drm: Add NVIDIA Tegra20 support
    On 09.11.2012 23:03, Thierry Reding wrote:
    > On Fri, Nov 09, 2012 at 10:26:27AM -0600, Rob Clark wrote:
    >> hmm, are these values defined by the hw? They look like register
    >> offsets into the DC block?
    > I don't think they are defined by the hardware. From what I gather these
    > can arbitrarily be assigned by software. If things actually work the way
    > I think they do, then eventually these values could be allocated by the
    > host1x_register_client() function and stored within the host1x_client
    > structure, so that each HW block can program them into the corresponding
    > register.
    These are host1x sync points. Sync points are used to synchronize work
    between host1x, host1x client units (like DC, 2D, EPP, etc), and CPU.
    Tegra2 TRM now contains chapters for HOST1X, 2D and EPP, so it has some
    more details.

    The assignment of sync points is a software policy. Depending on
    programming model of client unit, one or more sync points are used for
    each. For example, for each DC we have one sync point assigned to
    vblank, and one for each DC window. For 2D, we'd have one sync point,
    and a choice of using the same of different sync point for EPP.

    We could either assign sync point registers by hard coding, or assign
    them dynamically one per client unit, and possibly an additional one
    depending on the programming model. Sync points are a scarce resource,
    so we've so far preferred to do static assignment to catch
    overallocation as early as possible.

    Terje


    \
     
     \ /
      Last update: 2012-11-10 19:21    [W:7.193 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site