Negative deltas are used to fake a range in a large buffer. See 900a5c91eeb3 "i965: Use negative relocation deltas to minimise vertex uploads"
Gen8+ use 48-bit address relocations so need to extend the sign to 64-bit return value. Without it we have higher bits zeroed and missing the negavive values. Haswell and older use 32-bit deltas so are unaffected by this issue. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101408 Signed-off-by: Sergii Romantsov <sergii.romant...@globallogic.com> Tested-by: Andriy Khulap <andriy.khu...@globallogic.com> --- src/mesa/drivers/dri/i965/intel_batchbuffer.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c b/src/mesa/drivers/dri/i965/intel_batchbuffer.c index d824ff2..128da77 100644 --- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c +++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c @@ -1124,8 +1124,10 @@ emit_reloc(struct intel_batchbuffer *batch, /* Using the old buffer offset, write in what the right data would be, in * case the buffer doesn't move and we can short-circuit the relocation * processing in the kernel + * + * Some target_offsets may be negative, so extend the sign to 64 bits. */ - return entry->offset + target_offset; + return entry->offset + (int64_t)((int32_t)target_offset); } uint64_t -- 2.7.4 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
