[PATCH v1 4/4] staging: fbtft: hx8353d: send LUT via buffer to reduce stack usage
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STALE275d
From: Sun Jian <hidden>
Date: 2026-01-04 12:11:41
Also in:
dri-devel, linux-staging
Subsystem:
fbtft framebuffer drivers, staging subsystem, the rest · Maintainers:
Andy Shevchenko, Greg Kroah-Hartman, Linus Torvalds
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 <redacted> --- 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) {
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2.43.0