<div dir="ltr">Hi Dave,<div>Thanks for your feedback. No issue found actually if I remove "volatile" on my platform. In my experience, if the value is volatile, adding "volatile" will be safer and no harm, that is why I add it by default. If you think it is not necessary, it's ok for me to remove it.</div><div> </div><div>Regards,</div><div> </div><div>Y.C. Chen</div></div> <div class="gmail_quote"><div dir="ltr">Dave Airlie <<a href="mailto:airlied@gmail.com">airlied@gmail.com</a>> 於 2018年11月22日週四上午9:15寫道： </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Wed, 31 Oct 2018 at 18:12, Y.C. Chen <<a href="mailto:yacheng600221@gmail.com" target="_blank">yacheng600221@gmail.com</a>> wrote: > > From: "Y.C. Chen" <<a href="mailto:yc_chen@aspeedtech.com" target="_blank">yc_chen@aspeedtech.com</a>> > > v1: over-sample data to increase the stability with some specific monitors > v2: refine to avoid infinite loop This contains at least 4 whitespace breakages (val =) in a few places, also why the volatiles, I don't think they make much sense here, have you verified they are required? Dave. > > Signed-off-by: Y.C. Chen <<a href="mailto:yc_chen@aspeedtech.com" target="_blank">yc_chen@aspeedtech.com</a>> > --- > drivers/gpu/drm/ast/ast_mode.c | 34 ++++++++++++++++++++++++++++------ > 1 file changed, 28 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c > index 5e77d45..092e9a7 100644 > --- a/drivers/gpu/drm/ast/ast_mode.c > +++ b/drivers/gpu/drm/ast/ast_mode.c > @@ -972,9 +972,20 @@ static int get_clock(void *i2c_priv) > { > struct ast_i2c_chan *i2c = i2c_priv; > struct ast_private *ast = i2c->dev->dev_private; > - uint32_t val; > + volatile uint32_t val, val2, count, pass; > + > + count = 0; > + pass = 0; > + val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01; > + do { > + val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01; > + if (val == val2) pass++; > + else { > + pass = 0; > + val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01; > + } > + } while ((pass < 5) && (count++ < 0x10000)); > > - val = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4; > return val & 1 ? 1 : 0; > } > > @@ -982,9 +993,20 @@ static int get_data(void *i2c_priv) > { > struct ast_i2c_chan *i2c = i2c_priv; > struct ast_private *ast = i2c->dev->dev_private; > - uint32_t val; > + volatile uint32_t val, val2, count, pass; > + > + count = 0; > + pass = 0; > + val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01; > + do { > + val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01; > + if (val == val2) pass++; > + else { > + pass = 0; > + val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01; > + } > + } while ((pass < 5) && (count++ < 0x10000)); > > - val = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5; > return val & 1 ? 1 : 0; > } > > @@ -997,7 +1019,7 @@ static void set_clock(void *i2c_priv, int clock) > > for (i = 0; i < 0x10000; i++) { > ujcrb7 = ((clock & 0x01) ? 0 : 1); > - ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xfe, ujcrb7); > + ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf4, ujcrb7); > jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x01); > if (ujcrb7 == jtemp) > break; > @@ -1013,7 +1035,7 @@ static void set_data(void *i2c_priv, int data) > > for (i = 0; i < 0x10000; i++) { > ujcrb7 = ((data & 0x01) ? 0 : 1) << 2; > - ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xfb, ujcrb7); > + ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf1, ujcrb7); > jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x04); > if (ujcrb7 == jtemp) > break; > -- > 1.8.3.1 > > _______________________________________________ > dri-devel mailing list > <a href="mailto:dri-devel@lists.freedesktop.org" target="_blank">dri-devel@lists.freedesktop.org</a> > <a href="https://lists.freedesktop.org/mailman/listinfo/dri-devel" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/dri-devel</a> </blockquote></div>