Hi,
On 28/12/2021 10:25, Miles Chen wrote:
Fix unused-but-set variable warning:
drivers/gpu/drm/mediatek/mtk_cec.c:85:6: warning: variable 'tmp' set but not used [-Wunused-but-set-variable]
Actually we ignore the value passed to mtk_cec_mask. In case of mtk_cec_mask(cec, CEC_CKGEN, 0 | CEC_32K_PDN, PDN | CEC_32K_PDN);
We are not setting CEC_32K_PDN. I wonder which side effect will it have to set that bit.
I am confused about "not setting CEC_32K_PDN" part, in case mtk_cec_mask(cec, CEC_CKGEN, 0 | CEC_32K_PDN, PDN | CEC_32K_PDN); CEC_32K_PDN (BIT(19)) is set.
for exmaple: CEC_32K_PDN is BIT(19) PDN is BIT(16) say tmp = 0xffffffff;
mask = PDN | CEC_32K_PDN; val = 0 | CEC_32K_PDN;
tmp = fff6ffff, mask = 90000 val = 80000, tmp = fffeffff
u32 tmp = readl(cec->regs + offset) & ~mask; // tmp = fff6ffff tmp |= val & mask; // tmp = fffeffff writel(val, cec->regs + offset); // val = 80000, tmp = fffeffff
in both val and tmp case, CEC_32K_PDN is set.
Anyway, if it's the right thing to do, we should add:
Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
I will add the Fixes tag, thanks.