Re: [PATCH] drm/msm/a6xx: use __always_unused to fix compiler warnings for gen7_* includes

[Abhinav Kumar]

On 6/4/2024 4:58 PM, Dmitry Baryshkov wrote:
> On Tue, Jun 04, 2024 at 02:51:04PM -0700, Abhinav Kumar wrote:
> > GCC diagnostic pragma method throws below warnings in some of the versions
> >
> > drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:16:9: warning: unknown option after '#pragma GCC diagnostic' kind [-Wpragmas]
> >   #pragma GCC diagnostic ignored "-Wunused-const-variable"
> >           ^
> > In file included from drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:18:0:
> > drivers/gpu/drm/msm/adreno/adreno_gen7_0_0_snapshot.h:924:19: warning: 'gen7_0_0_external_core_regs__always_unused' defined but not used [-Wunused-variable]
> >   static const u32 *gen7_0_0_external_core_regs__always_unused[] = {
> >                     ^
>
> I don't see this symbol in upstream.

This was a C&P mistake. Instead of pasting the warning message from the 
default msm-next, I pasted the warning message from one of my trial runs 
(a bad one). I will fix the commit message when I post a v2.

The correct warnings are:

drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:16:9: warning: unknown 
option after '#pragma GCC diagnostic' kind [-Wpragmas]
 #pragma GCC diagnostic ignored "-Wunused-const-variable"
         ^
In file included from drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:18:0:
drivers/gpu/drm/msm/adreno/adreno_gen7_0_0_snapshot.h:924:19: warning: 
'gen7_0_0_external_core_regs' defined but not used [-Wunused-variable]
 static const u32 *gen7_0_0_external_core_regs[] = {
                   ^
In file included from drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:19:0:
drivers/gpu/drm/msm/adreno/adreno_gen7_2_0_snapshot.h:748:19: warning: 
'gen7_2_0_external_core_regs' defined but not used [-Wunused-variable]
 static const u32 *gen7_2_0_external_core_regs[] = {
                   ^
In file included from drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:20:0:
drivers/gpu/drm/msm/adreno/adreno_gen7_9_0_snapshot.h:1188:43: warning: 
'gen7_9_0_sptp_clusters' defined but not used [-Wunused-variable]
 static struct gen7_sptp_cluster_registers gen7_9_0_sptp_clusters[] = {
                                           ^
drivers/gpu/drm/msm/adreno/adreno_gen7_9_0_snapshot.h:1438:19: warning: 
'gen7_9_0_external_core_regs' defined but not used [-Wunused-variable]
 static const u32 *gen7_9_0_external_core_regs[] = {


> > In file included from drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:19:0:
> > drivers/gpu/drm/msm/adreno/adreno_gen7_2_0_snapshot.h:748:19: warning: 'gen7_2_0_external_core_regs' defined but not used [-Wunused-variable]
> >   static const u32 *gen7_2_0_external_core_regs[] = {
> >                     ^
> > In file included from drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c:20:0:
> > drivers/gpu/drm/msm/adreno/adreno_gen7_9_0_snapshot.h:1188:43: warning: 'gen7_9_0_sptp_clusters' defined but not used [-Wunused-variable]
> >   static struct gen7_sptp_cluster_registers gen7_9_0_sptp_clusters[] = {
> >                                             ^
> > drivers/gpu/drm/msm/adreno/adreno_gen7_9_0_snapshot.h:1438:19: warning: 'gen7_9_0_external_core_regs' defined but not used [-Wunused-variable]
> >   static const u32 *gen7_9_0_external_core_regs[] = {
> >
> > Remove GCC dependency by using __always_unused for the unused gen7_* includes.
> >
> > Fixes: 64d6255650d4 ("drm/msm: More fully implement devcoredump for a7xx")
> > Suggested-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> > Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c | 13 ++++---------
> >   1 file changed, 4 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
> > index 0a7717a4fc2f..62ca0cf24005 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
> > @@ -8,19 +8,10 @@
> >   #include "a6xx_gpu_state.h"
> >   #include "a6xx_gmu.xml.h"
> >   
> > -/* Ignore diagnostics about register tables that we aren't using yet. We don't
> > - * want to modify these headers too much from their original source.
> > - */
> > -#pragma GCC diagnostic push
> > -#pragma GCC diagnostic ignored "-Wunused-variable"
> > -#pragma GCC diagnostic ignored "-Wunused-const-variable"
> > -
> >   #include "adreno_gen7_0_0_snapshot.h"
> >   #include "adreno_gen7_2_0_snapshot.h"
> >   #include "adreno_gen7_9_0_snapshot.h"
> >   
> > -#pragma GCC diagnostic pop
> > -
> >   struct a6xx_gpu_state_obj {
> >   	const void *handle;
> >   	u32 *data;
> > @@ -1350,6 +1341,10 @@ static void a7xx_get_registers(struct msm_gpu *gpu,
> >   	int index = 0;
> >   	const u32 *pre_crashdumper_regs;
> >   	const struct gen7_reg_list *reglist;
> > +	__always_unused const u32 **external_core_regs7_0_0 = gen7_0_0_external_core_regs;
> > +	__always_unused const u32 **external_core_regs_7_2_0 = gen7_2_0_external_core_regs;
> > +	__always_unused const u32 **external_core_regs_7_9_0 = gen7_9_0_external_core_regs;
> > +	__always_unused struct gen7_sptp_cluster_registers *sptp_gen7 = gen7_9_0_sptp_clusters;
>
> Wouldn't it be easier to add something like the following to the
> a6xx_gpu_state.c before including the headers:
>
> static const unsigned int *gen7_0_0_external_core_regs[] __attribute((__unused__));
> static const unsigned int *gen7_2_0_external_core_regs[] __attribute((__unused__));
> static const unsigned int *gen7_9_0_external_core_regs[] __attribute((__unused__));

Ack, this works too and its cleaner. let me push it this way. Thanks.

> >   
> >   	if (adreno_is_a730(adreno_gpu)) {
> >   		reglist = gen7_0_0_reg_list;
> > --
> > 2.44.0