I tried to capture an image from SGRBG10_1X10/3280x2464 camera sensor on db845c board (sdm845), and from SRGGB10_1X10/3280x2464 camera sensor on RB5 (qrb5165 / sm8250). The captured frames contained incorrect image. These formats are 4100 bytes per line. 4100 aligned by 8 is 4104. 4100 aligned by 16 is 4112. After looking at the frame data captured with the current bpl_alignment value of 8 bytes, it becomes clear that the lines are not 4104 bytes long, but are actually 4112 bytes long. That is the current bpl_alignment value is set incorrectly. With bpl_alignment set to 8 bytes (the value currently used by the camss driver): * on db845c capturing may stall after a few frames are captured OK * the captured frames are corrupted: As the actual stride is 8 bytes more than expected, the 2nd line has 8 bytes from the 1st line tail in the beginning, and the actual data in the 2nd line are offset by these 8 bytes; the 3d line data are offset by 16 bytes etc. When the offset reaches the line length, one line starts with 0 offset again, the next line gets 8-byte offset etc. This results in "chainsaw shift" of lines in the captured image and messed up colours. Also a small part from the end of the actual frame (8 bytes times frame height) is not captured as it doesn't fit into the allocated buffer. * "arm-smmu: Unhandled context fault" messages in dmesg output Changing bpl_alignment to 16 bytes fixed all these issues: * no capture stalls on db845c * correct image in the captured frames * "arm-smmu: Unhandled context fault" messages are gone I've also used the patch https://lore.kernel.org/lkml/20230503075340.45755-1-y.oudjana@xxxxxxxxxxxxxx/ as without it the camss driver is broken in media_tree - yavta fails with error 22 (invalid argument). Here is an example console log from db845c with bpl_alignment=8 (stride 4104): -----8<----- $ yavta -B capture-mplane --capture=5 -n 5 -I -f SGRBG10P -s 3280x2464 --file=ov8856-SGRBG10-3280x2464-#.bin /dev/video6 Device /dev/video6 opened. Device `Qualcomm Camera Subsystem' on `platform:acb3000.camss' (driver 'qcom-camss') supports video, capture, with mplanes. Video format set: SGRBG10P (41416770) 3280x2464 field none, 1 planes: * Stride 4104, buffer size 10112256 Video format: SGRBG10P (41416770) 3280x2464 field none, 1 planes: * Stride 4104, buffer size 10112256 5 buffers requested. length: 1 offset: 4098861152 timestamp type/source: mono/EoF Buffer 0/0 mapped at address 0xffffa305b000. <snip> length: 1 offset: 4098861152 timestamp type/source: mono/EoF Buffer 4/0 mapped at address 0xffffa09c7000. 0 (0) [-] none 0 10112256 B 818.593063 818.594398 8.942 fps ts mono/EoF 1 (1) [-] none 1 10112256 B 818.661186 818.662596 14.679 fps ts mono/EoF 2 (2) [-] none 2 10112256 B 818.727812 818.729342 15.009 fps ts mono/EoF 3 (3) [-] none 3 10112256 B 818.781710 818.794871 18.554 fps ts mono/EoF <stalls after 4 of 5 frames captured> ^C $ -----8<----- The corresponding part of dmesg output: -----8<----- [ 658.608956] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0xff9a5000, fsynr=0x3c0013, cbfrsynra=0x810, cb=14 [ 658.676875] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0xfd9a5000, fsynr=0x3c0013, cbfrsynra=0x810, cb=14 [ 658.743863] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0xfc9a5000, fsynr=0x3c0013, cbfrsynra=0x810, cb=14 [ 658.810016] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0xfb9a5000, fsynr=0x3c0013, cbfrsynra=0x810, cb=14 ### several seconds after Ctrl-C is pressed at the console: [ 670.950533] qcom-camss acb3000.camss: VFE idle timeout - resetting -----8<----- Andrey Konovalov (1): media: camss: set VFE bpl_alignment to 16 for sdm845 and sm8250 drivers/media/platform/qcom/camss/camss-vfe.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) -- 2.34.1
