From: Sun Jian <sun.jian.kdev@gmail.com>
To: Andy Shevchenko <andy@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-staging@lists.linux.dev, linux-fbdev@vger.kernel.org,
dri-devel@lists.freedesktop.org,
Sun Jian <sun.jian.kdev@gmail.com>
Subject: [PATCH v1 4/4] staging: fbtft: hx8353d: send LUT via buffer to reduce stack usage
Date: Sun, 4 Jan 2026 19:06:38 +0800 [thread overview]
Message-ID: <20260104110638.532615-5-sun.jian.kdev@gmail.com> (raw)
In-Reply-To: <20260104110638.532615-1-sun.jian.kdev@gmail.com>
Clang reports a large stack frame in init_display()
(-Wframe-larger-than=1024) due to the very large
write_reg(MIPI_DCS_WRITE_LUT, ...) call.
Send MIPI_DCS_WRITE_LUT followed by the LUT payload using
fbtft_write_buf_dc() to avoid the varargs/NUMARGS stack blow-up.
No functional change intended.
Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
---
drivers/staging/fbtft/fb_hx8353d.c | 38 ++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 10 deletions(-)
diff --git a/drivers/staging/fbtft/fb_hx8353d.c b/drivers/staging/fbtft/fb_hx8353d.c
index 3e73b69b6a27..7e667d60792f 100644
--- a/drivers/staging/fbtft/fb_hx8353d.c
+++ b/drivers/staging/fbtft/fb_hx8353d.c
@@ -17,6 +17,21 @@
#define DRVNAME "fb_hx8353d"
#define DEFAULT_GAMMA "50 77 40 08 BF 00 03 0F 00 01 73 00 72 03 B0 0F 08 00 0F"
+static const u8 lut[] = {
+ 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,
+ 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62,
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+ 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+ 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
+ 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
+ 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,
+ 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62,
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+ 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+ 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
+ 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
+ };
+
static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
@@ -48,18 +63,21 @@ static int init_display(struct fbtft_par *par)
write_reg(par, MIPI_DCS_SET_DISPLAY_ON);
/* RGBSET */
- write_reg(par, MIPI_DCS_WRITE_LUT,
- 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,
- 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62,
- 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
- 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
- 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
- 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
- 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,
- 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62);
+ {
+ u8 cmd = MIPI_DCS_WRITE_LUT;
+ int ret;
+
+ ret = fbtft_write_buf_dc(par, &cmd, 1, 0);
+ if (ret < 0)
+ return ret;
+
+ ret = fbtft_write_buf_dc(par, (void *)lut, sizeof(lut), 1);
+ if (ret < 0)
+ return ret;
+ }
return 0;
-};
+}
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
--
2.43.0
next prev parent reply other threads:[~2026-01-04 11:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-04 11:06 [PATCH v1 0/4] staging: fbtft: reduce stack usage by avoiding large write_reg() varargs Sun Jian
2026-01-04 11:06 ` [PATCH v1 1/4] staging: fbtft: core: avoid large stack usage in DT init parsing Sun Jian
2026-01-05 16:28 ` Andy Shevchenko
2026-01-05 17:00 ` sun jian
2026-01-05 18:15 ` Andy Shevchenko
2026-01-06 0:42 ` sun jian
2026-01-04 11:06 ` [PATCH v1 2/4] staging: fbtft: ssd1351: send gamma table via fbtft_write_buf_dc() Sun Jian
2026-01-05 14:39 ` Dan Carpenter
2026-01-05 15:09 ` sun jian
2026-01-04 11:06 ` [PATCH v1 3/4] staging: fbtft: ssd1331: " Sun Jian
2026-01-04 11:06 ` Sun Jian [this message]
2026-01-05 16:36 ` [PATCH v1 4/4] staging: fbtft: hx8353d: send LUT via buffer to reduce stack usage Andy Shevchenko
2026-01-05 16:32 ` [PATCH v1 0/4] staging: fbtft: reduce stack usage by avoiding large write_reg() varargs Andy Shevchenko
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