On 07/05/18 17:19, Mauro Carvalho Chehab wrote: > Em Mon, 07 May 2018 16:26:08 +0300 > Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> escreveu: > >> Hi Mauro, >> >> On Saturday, 5 May 2018 19:08:15 EEST Mauro Carvalho Chehab wrote: >>> There was a recent discussion about the use/abuse of GFP_DMA flag when >>> allocating memories at LSF/MM 2018 (see Luis notes enclosed). >>> >>> The idea seems to be to remove it, using CMA instead. Before doing that, >>> better to check if what we have on media is are valid use cases for it, or >>> if it is there just due to some misunderstanding (or because it was >>> copied from some other code). >>> >>> Hans de Goede sent us today a patch stopping abuse at gspca, and I'm >>> also posting today two other patches meant to stop abuse of it on USB >>> drivers. Still, there are 4 platform drivers using it: >>> >>> $ git grep -l -E "GFP_DMA\\b" drivers/media/ >>> drivers/media/platform/omap3isp/ispstat.c >>> drivers/media/platform/sti/bdisp/bdisp-hw.c >>> drivers/media/platform/sti/hva/hva-mem.c Hi Mauro, The two STI drivers (bdisp-hw.c and hva-mem.c) are only expected to run on ARM platforms, not on x86. Since this thread deals with x86 & DMA trouble, I am not sure that we actually have a problem for the sti drivers. There are some other sti drivers that make use of this GFP_DMA flag (drivers/gpu/drm/sti/sti_*.c) and it does not seem to be a problem. Nevertheless I can see that the media sti drivers depend on COMPILE_TEST (which is not the case for the DRM ones). Would it be an acceptable solution to remove the COMPILE_TEST dependency? BR Fabien >>> drivers/media/spi/cxd2880-spi.c >>> >>> Could you please check if GFP_DMA is really needed there, or if it is >>> just because of some cut-and-paste from some other place? >> I started looking at that for the omap3isp driver but Sakari beat me at >> submitting a patch. GFP_DMA isn't needed for omap3isp. >> > Thank you both for looking into it. > > Regards, > Mauro > > > > Thanks, > Mauro
