I’m running 3.8.1 on Windows 10. The center darkroom view fails when a blend mode is invoked. The exported image is ok and the center view is restored if I turn on the clipping indication and turn it off again.
This seems to be a bug introduced in 3.8. If so, how should I report and document this?
The following screen shots illustrate the problem:
The OpenCl scheduling profile was set to “multiple GPU’s” (caused by the new performance option settings?). If the profile is set to “default” everything works ok.
My pc has embedded Intel Graphics and a NVIDIA GeForce GTX 850M. Does this count for multiple GPU’s?
If it works ok without OpenCL, then there is an issue with one of your two OpenCL drivers/card. The log file can help troubleshoot. Make sure you uninstall OpenCl compatibility from windows apps if it is installed.
I read a lot of information in the manual to turn on some debug settings, but I cannot see any debug information. Where can I find those debug logs?
The Windows version of dt by default logs its debug information to the following places:Windows 10: C:\Users\[username]\AppData\Local\Microsoft\Windows\INetCache\darktable\darktable-log.txt
Windows 7: C:\Users\[username]\AppData\Local\Microsoft\Windows\Temporary Internet Files\darktable\darktable-log.txt
When I try to open the log file using notepad, the file doesn’t exist. The log file is a hidden file, but I have opened it several times in the past (I just forgot how to locate it).
Darktable starts ok using the command:
Start C:“Program Files”\darktable\bin\darktable.exe -d all > log.txt 2>&1
But this doesn’t create a log file as mentioned in your post.
After some experimenting, I have discovered the following:
When DT OpenCL use my Intel Graphics exclusively then the central view, the navigation view , the thumbnail and the exported image is screwed up when the image has been edited by means of the multiply blend mode (and others as well).
When Intel Graphics is excluded from use by the appropriate setting of the configuration parameter “opencl_device_priority” then everything works correctly.
The reason for this problem to surface now is that the installation of 3.8.1 changed the opencl scheduling profile from “default” to “multiple devices” so that OpenCL now ignores my previous setting of “opencl_device_priority” to favour my NVIDIA graphics.
You could think that my Intel graphics is failing but it turns out that my NVIDIA graphics is only being used when running DT, all other work including video, displaying photos etc. has been correctly handled by the Intel graphics for several years. So it’s OpenCL’s use of the Intel Graphics that is in error.
Can this be fixed and how?
Moreover, and most important: I need to be able to generate a log file as I have done several times in the past. When running the latest version of Windows 10/DT 3.8.1. this is no longer possible the way you mention in your post and as stated in the DT documentation.
Intel OpenCL does cause problems. It also might not help if it is not a real graphics card. Some are just a section of the CPU. Avoid using it in the darktablerc is a good option.
I dont think the install changed the settings from default to multiple GPU.
DT is using OpenCL to do mathematical calculations and not for graphics. GPU cards are great at doing multiple math calculations used by games.
Thank you for your reply.
I understand that it is not worthwhile to investigate into why the combination of OpenCL and Intel Graphics doesn’t work. Ok, that’s fine with me.
Starting darktable without the log stuff doesn’t produce the anticipated log file.
Just guessing but if the Intel driver dynamically manages memory maybe when you use the blend mode it doesn’t have enough or leave enough for the OS…maybe you could tweak the Opencl settings for the intel graphics…not sure if headroom or mandatory memory allocation in the OpenCL parameters would help but you could try…there were at least two threads recently with lots of discussion around Opencl tweaking…I think even with the recent changes the discussion there should still be valid?? For sure and apologies if I missed it make sure you have the most up to date driver…one user a while back was having all sorts of issues on a laptop with Intel graphics and a driver update completely fixed it…again you may be up to date so this point could be irrelevant
Bill explained this on the darktable LUA scripts page …
Windows
Open a command prompt. Start darktable with the command “C:\Program Files\darktable\bin\darktable” -d lua > log.txt. This provides debugging information to give you insight into what is happening.
Keep in mind that you need sufficient permission to the working directory to both create the file and write to it.
You could try once without the redirection part (> log.txt). That probably won’t give you anything directly useful, but at least you’ll know there is something to write to the file.
I run DT on windows. I’m able to get to the log file created. I actually did yesterday since my Map is no longer working. I go to the darktable/bin location. Run darktable -d OpenCL and then go to the folder path i shared with you earlier in this thread.
