Hello, Chris. Thank you for reviewing patch.
Do you mean changing just only emit_reloc() parameter type or all the
preceding callers too?
Also, please, explain what you mean about patch cee9f3890351?
That issue is present even on mesa 13-0.0 and also solved with similar
type-conversion fix.
Regards, Sergii.
On Mon, Mar 26, 2018 at 3:31 PM, Chris Wilson <ch...@chris-wilson.co.uk>
wrote:
> Quoting Sergii Romantsov (2018-03-26 13:16:24)
> > 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
>
> Note that 48-bit relocations were only switched on in
> commit cee9f3890351 ("i965: Allow 48-bit addressing on Gen8+.")
> to save having to backport too far (although the patch is trivial).
>
> > 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);
>
> Although just changing s/uint32_t target_offset/int32_t target_offset/
> may be cleaner.
> -Chris
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--
Sergii Romantsov
GlobalLogic Inc.
www.globallogic.com
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