On 29/04/2020 00:53, Arnd Bergmann wrote:
Some older versions of gcc badly optimize code that passes
an inline function argument into another function by reference,
causing huge stack usage:
drivers/gpu/drm/bridge/tc358768.c: In function 'tc358768_bridge_pre_enable':
drivers/gpu/drm/bridge/tc358768.c:840:1: error: the frame size of 2256 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
Use a temporary variable as a workaround and add a comment pointing
to the gcc bug.
Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/gpu/drm/bridge/tc358768.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 1b39e8d37834..6650fe4cfc20 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -178,6 +178,8 @@ static int tc358768_clear_error(struct tc358768_priv *priv)
static void tc358768_write(struct tc358768_priv *priv, u32 reg, u32 val)
{
+ /* work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 */
+ int tmpval = val;
size_t count = 2;
if (priv->error)
@@ -187,7 +189,7 @@ static void tc358768_write(struct tc358768_priv *priv, u32 reg, u32 val)
if (reg < 0x100 || reg >= 0x600)
count = 1;
- priv->error = regmap_bulk_write(priv->regmap, reg, &val, count);
+ priv->error = regmap_bulk_write(priv->regmap, reg, &tmpval, count);
}
static void tc358768_read(struct tc358768_priv *priv, u32 reg, u32 *val)
tc358768_write is not inline. What is the inline function here? Or is tc358768_write optimized to
inline by the compiler?
Tomi
--
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