| Message ID | 20200220004232.GA28048@paulmck-ThinkPad-P72 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm_dp_mst_topology.c and old compilers | expand |
On Wed, Feb 19, 2020 at 7:42 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > Hello! > > A box with GCC 4.8.3 compiler didn't like drm_dp_mst_topology.c. The > following (lightly tested) patch makes it happy and seems OK for newer > compilers as well. > > Is this of interest? How about a memset instead? That should be consistent across compilers. Alex > > Thanx, Paul > > ----------------------------------------------------------------------- > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c > index 20cdaf3..232408a 100644 > --- a/drivers/gpu/drm/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c > @@ -5396,7 +5396,7 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port) > { > struct drm_dp_mst_port *immediate_upstream_port; > struct drm_dp_mst_port *fec_port; > - struct drm_dp_desc desc = { 0 }; > + struct drm_dp_desc desc = {{{ 0 }}}; > u8 endpoint_fec; > u8 endpoint_dsc; > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
Quoting Alex Deucher (2020-02-20 02:52:32) > On Wed, Feb 19, 2020 at 7:42 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > > > Hello! > > > > A box with GCC 4.8.3 compiler didn't like drm_dp_mst_topology.c. The > > following (lightly tested) patch makes it happy and seems OK for newer > > compilers as well. > > > > Is this of interest? > > How about a memset instead? That should be consistent across compilers. The kernel has adopted the gccism: struct drm_dp_desc desc = {}; git grep '= {}' | wc -l: 2046 git grep '= { }' | wc -l: 694 -Chris
On Wed, 2020-02-19 at 16:42 -0800, Paul E. McKenney wrote: > Hello! > > A box with GCC 4.8.3 compiler didn't like drm_dp_mst_topology.c. The > following (lightly tested) patch makes it happy and seems OK for newer > compilers as well. > > Is this of interest? [] > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c [] > @@ -5396,7 +5396,7 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port) > { > struct drm_dp_mst_port *immediate_upstream_port; > struct drm_dp_mst_port *fec_port; > - struct drm_dp_desc desc = { 0 }; > + struct drm_dp_desc desc = {{{ 0 }}}; Perhaps this is simpler as: struct drm_dp_desc desc = {};
On Thu, Feb 20, 2020 at 07:58:58AM +0000, Chris Wilson wrote: > Quoting Alex Deucher (2020-02-20 02:52:32) > > On Wed, Feb 19, 2020 at 7:42 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > > > > > Hello! > > > > > > A box with GCC 4.8.3 compiler didn't like drm_dp_mst_topology.c. The > > > following (lightly tested) patch makes it happy and seems OK for newer > > > compilers as well. > > > > > > Is this of interest? > > > > How about a memset instead? That should be consistent across compilers. > > The kernel has adopted the gccism: struct drm_dp_desc desc = {}; > git grep '= {}' | wc -l: 2046 > git grep '= { }' | wc -l: 694 > -Chris And this works well, a big "thank you!" to all three of you! Please see below for the updated patch. Thanx, Paul ------------------------------------------------------------------------ commit 78c0e53a98a9772a99e46806f8fcbe1140d667a4 Author: Paul E. McKenney <paulmck@kernel.org> Date: Wed Feb 19 16:42:47 2020 -0800 EXP drm: Make drm_dp_mst_dsc_aux_for_port() safe for old compilers Older compilers either want two extra pairs of curly braces around the initializer for local variable desc, or they want a single pair of curly braces with nothing inside. Current Linux-kernel practice favors the latter, so this commit makes it so. Suggested-by: Chris Wilson <chris@chris-wilson.co.uk> Suggested-by: Joe Perches <joe@perches.com> Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 20cdaf3..b123f60 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -5396,7 +5396,7 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port) { struct drm_dp_mst_port *immediate_upstream_port; struct drm_dp_mst_port *fec_port; - struct drm_dp_desc desc = { 0 }; + struct drm_dp_desc desc = { }; u8 endpoint_fec; u8 endpoint_dsc;
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 20cdaf3..232408a 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -5396,7 +5396,7 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port) { struct drm_dp_mst_port *immediate_upstream_port; struct drm_dp_mst_port *fec_port; - struct drm_dp_desc desc = { 0 }; + struct drm_dp_desc desc = {{{ 0 }}}; u8 endpoint_fec; u8 endpoint_dsc;