Hi,
Thanks for your replying.
I add printf into this kernel for dump gmin and gmax in this case on my
platform.
And I find that gmin has the value "0.00000" but gamx is 0.04.
But thold = gmin + (gmax * 0.5f). if gmin = 0.0f, it may cause thold has
only gmax / 2.
I think it may cause if (gval[g] <= thold) section will not be entered
because float caluclation may not be used equaltion comparation prcisionlly.
I am not familiar with the algorithm of demosaic.
If my patch is OK, could you please merge it and remove beignet from black
list?
Thanks.
Yan Wang
yan.wang
From: johannes hanika
Date: 2017-02-22 17:11
To: yan.wang
CC: darktable-dev
Subject: Re: Re: [darktable-dev] Darktable on Beignet
hi,
thanks for looking into this!
/0 is not nice in any case.. but i doubt your fix is the best we can
do. num should be incremented whenever a value is smaller than or
equal to a threshold, which is chosen based on the min and max of
these very values. the case num==0 should really never happen (and
it's not safeguarded in the cpu code path either).
at least the one case of the one gval[g] that is == gmin, the case
if(gval[g] <= thold) should trigger, no? the edge case being
gmin=gmax=thold which should be covered by the == case. maybe
something in the computation of these min and max went wrong?
cheers,
jo
On Wed, Feb 22, 2017 at 8:39 AM, yan.wang <[email protected]> wrote:
> Hi, Roman,
> I debugged darktable on beignet on my Skylake and Chrry View platfrom by
> your DNG and XMP files.
> I use the latest beignet master.
> The result seems some wrong with CPU version but is also different with
> screenshot result of bugzilla.
> Please review my attached screenshot file.
> For this issue, I found that it is related with the OCL kernel named
> with vng_interpolate() in demosaic_vng.cl.
> In this kernel, variable named with "num" may be zero and cause dividing
> zero error.
> After modify it like my attached patch, this issue will disappear.
> I haven't compared OCL kernel and CPU version.
> So I am not sure whether "num == 0" is right.
> I also will check the processing flow of "dividing zero" in Beignet.
> Thanks.
>
> ________________________________
> yan.wang
>
>
> From: Roman Lebedev
> Date: 2017-02-16 19:37
> To: yan.wang
> CC: darktable-dev
> Subject: Re: [darktable-dev] Darktable on Beignet
> On Thu, Feb 16, 2017 at 11:11 AM, yan.wang <[email protected]> wrote:
>> Hi,
>> I am Beignet devloper from Intel.
> Hi.
>
>> Just I found Beignet is pushed into the blacklist of darktable because
>> of one bug.
>> http://www.darktable.org/2016/12/darktable-2-2-0rc3-released/
>> I want to fix it but I don't know how to reproduce it.
> In this particular case, i blacklisted it because of
> https://redmine.darktable.org/issues/11358
>
> To reproduce, i guess you'd need
> https://redmine.darktable.org/attachments/download/2799/CRW_9672.DNG
> and https://redmine.darktable.org/attachments/download/2803/CRW_9672.DNG.xmp
>
> Disable blacklist (echo "opencl_disable_drivers_blacklist=true >>
> ~/.config/darktable/darktablerc")
> Start dt
> Import image
> Select it (highlight the image, click on it once)
> In right sidepanel, in "History stack" module, click on "load sidecar
> file", and select that XMP.
>
> Maybe this particular issue is already fixed, maybe it is not.
>
>> Who could help me?
>> Thanks.
>>
>> ________________________________
>> yan.wang
> Roman.
>
>>
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