* include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
@ 2025-12-05 10:16 kernel test robot
2025-12-30 2:47 ` Marek Vasut
0 siblings, 1 reply; 5+ messages in thread
From: kernel test robot @ 2025-12-05 10:16 UTC (permalink / raw)
To: Marek Vasut; +Cc: oe-kbuild-all, linux-kernel, Tomi Valkeinen
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 2061f18ad76ecaddf8ed17df81b8611ea88dbddd
commit: 4f716a1db661cfb31502a0a6d7e62c06daf2e603 drm/rcar-du: dsi: Convert register bitfields to GENMASK() macro
date: 5 weeks ago
config: arc-randconfig-001-20251205 (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512051834.bESvhDiG-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from <command-line>:
drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c: In function 'rcar_mipi_dsi_startup.isra.4':
>> include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
include/linux/compiler_types.h:578:4: note: in definition of macro '__compiletime_assert'
prefix ## suffix(); \
^~~~~~
include/linux/compiler_types.h:597:2: note: in expansion of macro '_compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:68:3: note: in expansion of macro 'BUILD_BUG_ON_MSG'
BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
^~~~~~~~~~~~~~~~
include/linux/bitfield.h:115:3: note: in expansion of macro '__BF_FIELD_CHECK'
__BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
^~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h:259:29: note: in expansion of macro 'FIELD_PREP'
#define VCLKSET_DIV_V4H(n) FIELD_PREP(VCLKSET_DIV_V4H_MASK, (n))
^~~~~~~~~~
drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c:660:14: note: in expansion of macro 'VCLKSET_DIV_V4H'
vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
^~~~~~~~~~~~~~~
--
In file included from <command-line>:
rcar_mipi_dsi.c: In function 'rcar_mipi_dsi_startup.isra.4':
>> include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
include/linux/compiler_types.h:578:4: note: in definition of macro '__compiletime_assert'
prefix ## suffix(); \
^~~~~~
include/linux/compiler_types.h:597:2: note: in expansion of macro '_compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:68:3: note: in expansion of macro 'BUILD_BUG_ON_MSG'
BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
^~~~~~~~~~~~~~~~
include/linux/bitfield.h:115:3: note: in expansion of macro '__BF_FIELD_CHECK'
__BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
^~~~~~~~~~~~~~~~
rcar_mipi_dsi_regs.h:259:29: note: in expansion of macro 'FIELD_PREP'
#define VCLKSET_DIV_V4H(n) FIELD_PREP(VCLKSET_DIV_V4H_MASK, (n))
^~~~~~~~~~
rcar_mipi_dsi.c:660:14: note: in expansion of macro 'VCLKSET_DIV_V4H'
vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
^~~~~~~~~~~~~~~
vim +/__compiletime_assert_437 +597 include/linux/compiler_types.h
eb5c2d4b45e3d2 Will Deacon 2020-07-21 583
eb5c2d4b45e3d2 Will Deacon 2020-07-21 584 #define _compiletime_assert(condition, msg, prefix, suffix) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21 585 __compiletime_assert(condition, msg, prefix, suffix)
eb5c2d4b45e3d2 Will Deacon 2020-07-21 586
eb5c2d4b45e3d2 Will Deacon 2020-07-21 587 /**
eb5c2d4b45e3d2 Will Deacon 2020-07-21 588 * compiletime_assert - break build and emit msg if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21 589 * @condition: a compile-time constant condition to check
eb5c2d4b45e3d2 Will Deacon 2020-07-21 590 * @msg: a message to emit if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21 591 *
eb5c2d4b45e3d2 Will Deacon 2020-07-21 592 * In tradition of POSIX assert, this macro will break the build if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21 593 * supplied condition is *false*, emitting the supplied error message if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21 594 * compiler has support to do so.
eb5c2d4b45e3d2 Will Deacon 2020-07-21 595 */
eb5c2d4b45e3d2 Will Deacon 2020-07-21 596 #define compiletime_assert(condition, msg) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21 @597 _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
eb5c2d4b45e3d2 Will Deacon 2020-07-21 598
:::::: The code at line 597 was first introduced by commit
:::::: eb5c2d4b45e3d2d5d052ea6b8f1463976b1020d5 compiler.h: Move compiletime_assert() macros into compiler_types.h
:::::: TO: Will Deacon <will@kernel.org>
:::::: CC: Will Deacon <will@kernel.org>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
2025-12-05 10:16 include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field kernel test robot
@ 2025-12-30 2:47 ` Marek Vasut
2025-12-30 10:30 ` Laurent Pinchart
2025-12-30 23:02 ` David Laight
0 siblings, 2 replies; 5+ messages in thread
From: Marek Vasut @ 2025-12-30 2:47 UTC (permalink / raw)
To: kernel test robot, Tomi Valkeinen, Laurent Pinchart
Cc: oe-kbuild-all, linux-kernel,
open list:MEDIA DRIVERS FOR RENESAS - FCP
On 12/5/25 11:16 AM, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 2061f18ad76ecaddf8ed17df81b8611ea88dbddd
> commit: 4f716a1db661cfb31502a0a6d7e62c06daf2e603 drm/rcar-du: dsi: Convert register bitfields to GENMASK() macro
> date: 5 weeks ago
> config: arc-randconfig-001-20251205 (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/config)
> compiler: arc-linux-gcc (GCC) 8.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202512051834.bESvhDiG-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
> In file included from <command-line>:
> drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c: In function 'rcar_mipi_dsi_startup.isra.4':
>>> include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
[...]
> rcar_mipi_dsi.c:660:14: note: in expansion of macro 'VCLKSET_DIV_V4H'
> vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
> ^~~~~~~~~~~~~~~
I don't think this condition can occur.
In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
- rcar_mipi_dsi_startup() calls rcar_mipi_dsi_parameters_calc() which is
the only site that assigns setup_info.vclk_divider this way:
415 switch (dsi->info->model) {
416 case RCAR_DSI_V3U:
417 default:
418 setup_info->vclk_divider = 1 <<
((clk_cfg->vco_cntrl >> 4) & 0x3);
419 break;
420
421 case RCAR_DSI_V4H:
422 setup_info->vclk_divider = 1 <<
(((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
423 break;
424 }
In case of V3U, vclk_divider is 1 << (0..3) .
In case of V4H, vclk_divider is 1 << (1..8) .
In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
- rcar_mipi_dsi_startup() later contains the offending code:
653 switch (dsi->info->model) {
654 case RCAR_DSI_V3U:
655 default:
656 vclkset |=
VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider));
657 break;
658
659 case RCAR_DSI_V4H:
660 vclkset |=
VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
661 break;
662 }
This does the reverse of the code that assigned the value above, so:
In case of V3U, field value is (0..3) .
In case of V4H, field value is (0..7) .
Finally in drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h :
256 #define VCLKSET_DIV_V3U_MASK GENMASK_U32(5, 4)
257 #define VCLKSET_DIV_V3U(n)
FIELD_PREP(VCLKSET_DIV_V3U_MASK, (n))
258 #define VCLKSET_DIV_V4H_MASK GENMASK_U32(6, 4)
259 #define VCLKSET_DIV_V4H(n)
FIELD_PREP(VCLKSET_DIV_V4H_MASK, (n))
The masks fit exactly. For V3U the mask is 2-bit, or V4H the mask is 3-bit .
...
I can however rewrite the code in this way, which should also mitigate
this warning. Do you think this makes the code any better ?
diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
index 4ef2e3c129ed7..20e2a4cae5b86 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
@@ -84,7 +84,6 @@ struct dsi_setup_info {
unsigned long fout;
u16 m;
u16 n;
- u16 vclk_divider;
const struct dsi_clk_config *clkset;
};
@@ -338,7 +337,8 @@ rcar_mipi_dsi_post_init_phtw_v4h(struct
rcar_mipi_dsi *dsi,
static void rcar_mipi_dsi_pll_calc(struct rcar_mipi_dsi *dsi,
unsigned long fin_rate,
unsigned long fout_target,
- struct dsi_setup_info *setup_info)
+ struct dsi_setup_info *setup_info,
+ u16 vclk_divider)
{
unsigned int best_err = -1;
const struct rcar_mipi_dsi_device_info *info = dsi->info;
@@ -391,6 +391,7 @@ static void rcar_mipi_dsi_parameters_calc(struct
rcar_mipi_dsi *dsi,
unsigned long fin_rate;
unsigned int i;
unsigned int err;
+ u16 vclk_divider;
/*
* Calculate Fout = dot clock * ColorDepth / (2 * Lane Count)
@@ -415,15 +416,15 @@ static void rcar_mipi_dsi_parameters_calc(struct
rcar_mipi_dsi *dsi,
switch (dsi->info->model) {
case RCAR_DSI_V3U:
default:
- setup_info->vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
+ vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
break;
case RCAR_DSI_V4H:
- setup_info->vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
+ vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
break;
}
- rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info);
+ rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info,
vclk_divider);
/* Find hsfreqrange */
setup_info->hsfreq = setup_info->fout * 2;
@@ -439,7 +440,7 @@ static void rcar_mipi_dsi_parameters_calc(struct
rcar_mipi_dsi *dsi,
dev_dbg(dsi->dev,
"Fout = %u * %lu / (%u * %u * %u) = %lu (target %lu Hz, error
%d.%02u%%)\n",
setup_info->m, fin_rate, dsi->info->n_mul, setup_info->n,
- setup_info->vclk_divider, setup_info->fout, fout_target,
+ vclk_divider, setup_info->fout, fout_target,
err / 100, err % 100);
dev_dbg(dsi->dev,
@@ -653,11 +654,11 @@ static int rcar_mipi_dsi_startup(struct
rcar_mipi_dsi *dsi,
switch (dsi->info->model) {
case RCAR_DSI_V3U:
default:
- vclkset |= VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider));
+ vclkset |= VCLKSET_DIV_V3U((clk_cfg->vco_cntrl >> 4) & 0x3);
break;
case RCAR_DSI_V4H:
- vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
+ vclkset |= VCLKSET_DIV_V4H((clk_cfg->vco_cntrl >> 3) & 0x7);
break;
}
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
2025-12-30 2:47 ` Marek Vasut
@ 2025-12-30 10:30 ` Laurent Pinchart
2025-12-31 15:05 ` Marek Vasut
2025-12-30 23:02 ` David Laight
1 sibling, 1 reply; 5+ messages in thread
From: Laurent Pinchart @ 2025-12-30 10:30 UTC (permalink / raw)
To: Marek Vasut
Cc: kernel test robot, Tomi Valkeinen, oe-kbuild-all, linux-kernel,
open list:MEDIA DRIVERS FOR RENESAS - FCP
On Tue, Dec 30, 2025 at 03:47:17AM +0100, Marek Vasut wrote:
> On 12/5/25 11:16 AM, kernel test robot wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head: 2061f18ad76ecaddf8ed17df81b8611ea88dbddd
> > commit: 4f716a1db661cfb31502a0a6d7e62c06daf2e603 drm/rcar-du: dsi: Convert register bitfields to GENMASK() macro
> > date: 5 weeks ago
> > config: arc-randconfig-001-20251205 (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/config)
> > compiler: arc-linux-gcc (GCC) 8.5.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202512051834.bESvhDiG-lkp@intel.com/
> >
> > All errors (new ones prefixed by >>):
> >
> > In file included from <command-line>:
> > drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c: In function 'rcar_mipi_dsi_startup.isra.4':
> >>> include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
>
> [...]
>
> > rcar_mipi_dsi.c:660:14: note: in expansion of macro 'VCLKSET_DIV_V4H'
> > vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
> > ^~~~~~~~~~~~~~~
> I don't think this condition can occur.
>
> In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
> - rcar_mipi_dsi_startup() calls rcar_mipi_dsi_parameters_calc() which is
> the only site that assigns setup_info.vclk_divider this way:
>
> 415 switch (dsi->info->model) {
> 416 case RCAR_DSI_V3U:
> 417 default:
> 418 setup_info->vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
> 419 break;
> 420
> 421 case RCAR_DSI_V4H:
> 422 setup_info->vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
> 423 break;
> 424 }
>
> In case of V3U, vclk_divider is 1 << (0..3) .
> In case of V4H, vclk_divider is 1 << (1..8) .
>
> In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
> - rcar_mipi_dsi_startup() later contains the offending code:
>
> 653 switch (dsi->info->model) {
> 654 case RCAR_DSI_V3U:
> 655 default:
> 656 vclkset |= VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider));
> 657 break;
> 658
> 659 case RCAR_DSI_V4H:
> 660 vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
> 661 break;
> 662 }
>
> This does the reverse of the code that assigned the value above, so:
>
> In case of V3U, field value is (0..3) .
> In case of V4H, field value is (0..7) .
>
> Finally in drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h :
>
> 256 #define VCLKSET_DIV_V3U_MASK GENMASK_U32(5, 4)
> 257 #define VCLKSET_DIV_V3U(n)
> FIELD_PREP(VCLKSET_DIV_V3U_MASK, (n))
> 258 #define VCLKSET_DIV_V4H_MASK GENMASK_U32(6, 4)
> 259 #define VCLKSET_DIV_V4H(n)
> FIELD_PREP(VCLKSET_DIV_V4H_MASK, (n))
>
> The masks fit exactly. For V3U the mask is 2-bit, or V4H the mask is 3-bit .
>
> ...
>
> I can however rewrite the code in this way, which should also mitigate
> this warning. Do you think this makes the code any better ?
The datasheet says that the VCLKSET.DIV field "should be same as the
CLOCKSET2.vco_cntrl[5:3]". The change below makes this explicit, which
may not be a bad thing, even if it duplicates the small calculation.
> diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> index 4ef2e3c129ed7..20e2a4cae5b86 100644
> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> @@ -84,7 +84,6 @@ struct dsi_setup_info {
> unsigned long fout;
> u16 m;
> u16 n;
> - u16 vclk_divider;
> const struct dsi_clk_config *clkset;
> };
>
> @@ -338,7 +337,8 @@ rcar_mipi_dsi_post_init_phtw_v4h(struct
> rcar_mipi_dsi *dsi,
> static void rcar_mipi_dsi_pll_calc(struct rcar_mipi_dsi *dsi,
> unsigned long fin_rate,
> unsigned long fout_target,
> - struct dsi_setup_info *setup_info)
> + struct dsi_setup_info *setup_info,
> + u16 vclk_divider)
> {
> unsigned int best_err = -1;
> const struct rcar_mipi_dsi_device_info *info = dsi->info;
> @@ -391,6 +391,7 @@ static void rcar_mipi_dsi_parameters_calc(struct
> rcar_mipi_dsi *dsi,
> unsigned long fin_rate;
> unsigned int i;
> unsigned int err;
> + u16 vclk_divider;
>
> /*
> * Calculate Fout = dot clock * ColorDepth / (2 * Lane Count)
> @@ -415,15 +416,15 @@ static void rcar_mipi_dsi_parameters_calc(struct
> rcar_mipi_dsi *dsi,
> switch (dsi->info->model) {
> case RCAR_DSI_V3U:
> default:
> - setup_info->vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
> + vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
> break;
>
> case RCAR_DSI_V4H:
> - setup_info->vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
> + vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
> break;
> }
>
> - rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info);
> + rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info, vclk_divider);
>
> /* Find hsfreqrange */
> setup_info->hsfreq = setup_info->fout * 2;
> @@ -439,7 +440,7 @@ static void rcar_mipi_dsi_parameters_calc(struct rcar_mipi_dsi *dsi,
> dev_dbg(dsi->dev,
> "Fout = %u * %lu / (%u * %u * %u) = %lu (target %lu Hz, error %d.%02u%%)\n",
> setup_info->m, fin_rate, dsi->info->n_mul, setup_info->n,
> - setup_info->vclk_divider, setup_info->fout, fout_target,
> + vclk_divider, setup_info->fout, fout_target,
> err / 100, err % 100);
>
> dev_dbg(dsi->dev,
> @@ -653,11 +654,11 @@ static int rcar_mipi_dsi_startup(struct rcar_mipi_dsi *dsi,
> switch (dsi->info->model) {
> case RCAR_DSI_V3U:
> default:
> - vclkset |= VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider));
> + vclkset |= VCLKSET_DIV_V3U((clk_cfg->vco_cntrl >> 4) & 0x3);
> break;
>
> case RCAR_DSI_V4H:
> - vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
> + vclkset |= VCLKSET_DIV_V4H((clk_cfg->vco_cntrl >> 3) & 0x7);
> break;
> }
Laurent Pinchart
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
2025-12-30 2:47 ` Marek Vasut
2025-12-30 10:30 ` Laurent Pinchart
@ 2025-12-30 23:02 ` David Laight
1 sibling, 0 replies; 5+ messages in thread
From: David Laight @ 2025-12-30 23:02 UTC (permalink / raw)
To: Marek Vasut
Cc: kernel test robot, Tomi Valkeinen, Laurent Pinchart,
oe-kbuild-all, linux-kernel,
open list:MEDIA DRIVERS FOR RENESAS - FCP
On Tue, 30 Dec 2025 03:47:17 +0100
Marek Vasut <marek.vasut@mailbox.org> wrote:
> On 12/5/25 11:16 AM, kernel test robot wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head: 2061f18ad76ecaddf8ed17df81b8611ea88dbddd
> > commit: 4f716a1db661cfb31502a0a6d7e62c06daf2e603 drm/rcar-du: dsi: Convert register bitfields to GENMASK() macro
> > date: 5 weeks ago
> > config: arc-randconfig-001-20251205 (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/config)
> > compiler: arc-linux-gcc (GCC) 8.5.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202512051834.bESvhDiG-lkp@intel.com/
> >
> > All errors (new ones prefixed by >>):
> >
> > In file included from <command-line>:
> > drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c: In function 'rcar_mipi_dsi_startup.isra.4':
> >>> include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
>
> [...]
>
> > rcar_mipi_dsi.c:660:14: note: in expansion of macro 'VCLKSET_DIV_V4H'
> > vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
> > ^~~~~~~~~~~~~~~
> I don't think this condition can occur.
The value of vclk_divider makes no difference.
The compiler has generated a code path where a constant is passed to
FIELD_PREP().
At a guess 'arc' doesn't have a definition for __ffs(x) so the compiler
builtin in used (I've forgotten its name), but that probably has looks like:
#define __ffs(x) (__builtin_ffs(x) - 1)
where (effectively):
#define __builtin_ffs(x) (!x ? 0 : 1 + count_trailing_zeros(x))
That ?: condition ends up in the code and gcc moves the FIELD_PREP()
into it (gcc likes optimising arithmetic on constants).
So you end up with FIELD_PREP(mask, -1) - and hence the error.
>
> In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
> - rcar_mipi_dsi_startup() calls rcar_mipi_dsi_parameters_calc() which is
> the only site that assigns setup_info.vclk_divider this way:
>
> 415 switch (dsi->info->model) {
> 416 case RCAR_DSI_V3U:
> 417 default:
> 418 setup_info->vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
> 419 break;
> 420
> 421 case RCAR_DSI_V4H:
> 422 setup_info->vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
> 423 break;
> 424 }
>
> In case of V3U, vclk_divider is 1 << (0..3) .
> In case of V4H, vclk_divider is 1 << (1..8) .
>
> In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
> - rcar_mipi_dsi_startup() later contains the offending code:
>
> 653 switch (dsi->info->model) {
> 654 case RCAR_DSI_V3U:
> 655 default:
> 656 vclkset |= VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider));
> 657 break;
> 658
> 659 case RCAR_DSI_V4H:
> 660 vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
> 661 break;
> 662 }
>
> This does the reverse of the code that assigned the value above, so:
>
> In case of V3U, field value is (0..3) .
> In case of V4H, field value is (0..7) .
>
> Finally in drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h :
>
> 256 #define VCLKSET_DIV_V3U_MASK GENMASK_U32(5, 4)
> 257 #define VCLKSET_DIV_V3U(n) FIELD_PREP(VCLKSET_DIV_V3U_MASK, (n))
> 258 #define VCLKSET_DIV_V4H_MASK GENMASK_U32(6, 4)
> 259 #define VCLKSET_DIV_V4H(n) FIELD_PREP(VCLKSET_DIV_V4H_MASK, (n))
>
> The masks fit exactly. For V3U the mask is 2-bit, or V4H the mask is 3-bit .
The only other use I can see is:
fout = div64_u64(fout, setup_info->vclk_divider);
ISTM that there is an unnecessary '1 << n' and __ffs().
Perhaps you should be saving the 'bit number' not the shifted value.
The div64_u64() is then just a >> and fine on 32bit systems.
David
>
> ...
>
> I can however rewrite the code in this way, which should also mitigate
> this warning. Do you think this makes the code any better ?
>
> diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> index 4ef2e3c129ed7..20e2a4cae5b86 100644
> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c
> @@ -84,7 +84,6 @@ struct dsi_setup_info {
> unsigned long fout;
> u16 m;
> u16 n;
> - u16 vclk_divider;
> const struct dsi_clk_config *clkset;
> };
>
> @@ -338,7 +337,8 @@ rcar_mipi_dsi_post_init_phtw_v4h(struct
> rcar_mipi_dsi *dsi,
> static void rcar_mipi_dsi_pll_calc(struct rcar_mipi_dsi *dsi,
> unsigned long fin_rate,
> unsigned long fout_target,
> - struct dsi_setup_info *setup_info)
> + struct dsi_setup_info *setup_info,
> + u16 vclk_divider)
> {
> unsigned int best_err = -1;
> const struct rcar_mipi_dsi_device_info *info = dsi->info;
> @@ -391,6 +391,7 @@ static void rcar_mipi_dsi_parameters_calc(struct
> rcar_mipi_dsi *dsi,
> unsigned long fin_rate;
> unsigned int i;
> unsigned int err;
> + u16 vclk_divider;
>
> /*
> * Calculate Fout = dot clock * ColorDepth / (2 * Lane Count)
> @@ -415,15 +416,15 @@ static void rcar_mipi_dsi_parameters_calc(struct
> rcar_mipi_dsi *dsi,
> switch (dsi->info->model) {
> case RCAR_DSI_V3U:
> default:
> - setup_info->vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
> + vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
> break;
>
> case RCAR_DSI_V4H:
> - setup_info->vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
> + vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
> break;
> }
>
> - rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info);
> + rcar_mipi_dsi_pll_calc(dsi, fin_rate, fout_target, setup_info,
> vclk_divider);
>
> /* Find hsfreqrange */
> setup_info->hsfreq = setup_info->fout * 2;
> @@ -439,7 +440,7 @@ static void rcar_mipi_dsi_parameters_calc(struct
> rcar_mipi_dsi *dsi,
> dev_dbg(dsi->dev,
> "Fout = %u * %lu / (%u * %u * %u) = %lu (target %lu Hz, error
> %d.%02u%%)\n",
> setup_info->m, fin_rate, dsi->info->n_mul, setup_info->n,
> - setup_info->vclk_divider, setup_info->fout, fout_target,
> + vclk_divider, setup_info->fout, fout_target,
> err / 100, err % 100);
>
> dev_dbg(dsi->dev,
> @@ -653,11 +654,11 @@ static int rcar_mipi_dsi_startup(struct
> rcar_mipi_dsi *dsi,
> switch (dsi->info->model) {
> case RCAR_DSI_V3U:
> default:
> - vclkset |= VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider));
> + vclkset |= VCLKSET_DIV_V3U((clk_cfg->vco_cntrl >> 4) & 0x3);
> break;
>
> case RCAR_DSI_V4H:
> - vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
> + vclkset |= VCLKSET_DIV_V4H((clk_cfg->vco_cntrl >> 3) & 0x7);
> break;
> }
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
2025-12-30 10:30 ` Laurent Pinchart
@ 2025-12-31 15:05 ` Marek Vasut
0 siblings, 0 replies; 5+ messages in thread
From: Marek Vasut @ 2025-12-31 15:05 UTC (permalink / raw)
To: Laurent Pinchart, David Laight
Cc: kernel test robot, Tomi Valkeinen, oe-kbuild-all, linux-kernel,
open list:MEDIA DRIVERS FOR RENESAS - FCP
On 12/30/25 11:30 AM, Laurent Pinchart wrote:
> On Tue, Dec 30, 2025 at 03:47:17AM +0100, Marek Vasut wrote:
>> On 12/5/25 11:16 AM, kernel test robot wrote:
>>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>>> head: 2061f18ad76ecaddf8ed17df81b8611ea88dbddd
>>> commit: 4f716a1db661cfb31502a0a6d7e62c06daf2e603 drm/rcar-du: dsi: Convert register bitfields to GENMASK() macro
>>> date: 5 weeks ago
>>> config: arc-randconfig-001-20251205 (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/config)
>>> compiler: arc-linux-gcc (GCC) 8.5.0
>>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251205/202512051834.bESvhDiG-lkp@intel.com/reproduce)
>>>
>>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>>> the same patch/commit), kindly add following tags
>>> | Reported-by: kernel test robot <lkp@intel.com>
>>> | Closes: https://lore.kernel.org/oe-kbuild-all/202512051834.bESvhDiG-lkp@intel.com/
>>>
>>> All errors (new ones prefixed by >>):
>>>
>>> In file included from <command-line>:
>>> drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c: In function 'rcar_mipi_dsi_startup.isra.4':
>>>>> include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field
>>
>> [...]
>>
>>> rcar_mipi_dsi.c:660:14: note: in expansion of macro 'VCLKSET_DIV_V4H'
>>> vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
>>> ^~~~~~~~~~~~~~~
>> I don't think this condition can occur.
>>
>> In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
>> - rcar_mipi_dsi_startup() calls rcar_mipi_dsi_parameters_calc() which is
>> the only site that assigns setup_info.vclk_divider this way:
>>
>> 415 switch (dsi->info->model) {
>> 416 case RCAR_DSI_V3U:
>> 417 default:
>> 418 setup_info->vclk_divider = 1 << ((clk_cfg->vco_cntrl >> 4) & 0x3);
>> 419 break;
>> 420
>> 421 case RCAR_DSI_V4H:
>> 422 setup_info->vclk_divider = 1 << (((clk_cfg->vco_cntrl >> 3) & 0x7) + 1);
>> 423 break;
>> 424 }
>>
>> In case of V3U, vclk_divider is 1 << (0..3) .
>> In case of V4H, vclk_divider is 1 << (1..8) .
>>
>> In drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi.c :
>> - rcar_mipi_dsi_startup() later contains the offending code:
>>
>> 653 switch (dsi->info->model) {
>> 654 case RCAR_DSI_V3U:
>> 655 default:
>> 656 vclkset |= VCLKSET_DIV_V3U(__ffs(setup_info.vclk_divider));
>> 657 break;
>> 658
>> 659 case RCAR_DSI_V4H:
>> 660 vclkset |= VCLKSET_DIV_V4H(__ffs(setup_info.vclk_divider) - 1);
>> 661 break;
>> 662 }
>>
>> This does the reverse of the code that assigned the value above, so:
>>
>> In case of V3U, field value is (0..3) .
>> In case of V4H, field value is (0..7) .
>>
>> Finally in drivers/gpu/drm/renesas/rcar-du/rcar_mipi_dsi_regs.h :
>>
>> 256 #define VCLKSET_DIV_V3U_MASK GENMASK_U32(5, 4)
>> 257 #define VCLKSET_DIV_V3U(n)
>> FIELD_PREP(VCLKSET_DIV_V3U_MASK, (n))
>> 258 #define VCLKSET_DIV_V4H_MASK GENMASK_U32(6, 4)
>> 259 #define VCLKSET_DIV_V4H(n)
>> FIELD_PREP(VCLKSET_DIV_V4H_MASK, (n))
>>
>> The masks fit exactly. For V3U the mask is 2-bit, or V4H the mask is 3-bit .
>>
>> ...
>>
>> I can however rewrite the code in this way, which should also mitigate
>> this warning. Do you think this makes the code any better ?
>
> The datasheet says that the VCLKSET.DIV field "should be same as the
> CLOCKSET2.vco_cntrl[5:3]". The change below makes this explicit, which
> may not be a bad thing, even if it duplicates the small calculation.
I believe the following rework should address the duplication concern too:
https://lore.kernel.org/dri-devel/20251231145712.60816-1-marek.vasut+renesas@mailbox.org/
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2025-12-31 15:06 UTC | newest]
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2025-12-05 10:16 include/linux/compiler_types.h:597:38: error: call to '__compiletime_assert_437' declared with attribute error: FIELD_PREP: value too large for the field kernel test robot
2025-12-30 2:47 ` Marek Vasut
2025-12-30 10:30 ` Laurent Pinchart
2025-12-31 15:05 ` Marek Vasut
2025-12-30 23:02 ` David Laight
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