With devices that fetch data 'bottom up', there were two problems in the thread band logic. This caused VMerror messages and an infinite loop when it got lost. Although I am working on other improvements for customer 531 and customer 850, this patch will be applied as a minimal fix prior to the imminent release.
Created attachment 4250 [details] gxclthrd.c.diff When starting from the end of the page, the first band rendered needs to be (band_count - 1). Also the last band is band 0 so we need to start threads when next_band >= 0 (the previous test never started band 0, causing an infinite loop.
Ok to commit for the release.
Patch committed as rev. 8906