Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 04/04/18 12:51, Laurent Pinchart wrote:
> Hi Tomi,
> 
> On Wednesday, 4 April 2018 10:37:05 EEST Tomi Valkeinen wrote:
>> On 04/04/18 00:11, Laurent Pinchart wrote:
>>> I assume access to DMM-mapped buffers to be way more frequent than access
>>> to the DMM registers. If that's the case, this partial workaround should
>>> only slightly lower the probability of system lock-up. Do you have plans
>>> to implement a workaround that will fix the problem completely ?
>>
>> CPU only accesses memory via DMM when using TILER 2D buffers, which are
>> not officially supported. For non-2D, the pages are mapped directly to
>> the CPU without DMM in between.
> 
> What is the DMM used for with non-2D then ? Does it need to be setup at all ?

It creates a contiguous view of memory for IPs without IOMMUs, like DSS.

 Tomi

-- 
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux