On 2017-06-21 09:38, Daniel Vetter wrote:
> On Tue, Jun 20, 2017 at 09:25:25PM +0200, Peter Rosin wrote:
>> This makes the redundant fb helpers .load_lut, .gamma_set and .gamma_get
>> totally obsolete.
>>
>> I think the gamma_store can end up invalid on error. But the way I read
>> it, that can happen in drm_mode_gamma_set_ioctl as well, so why should
>> this pesky legacy fbdev stuff be any better?
>>
>> drm_fb_helper_save_lut_atomic justs saves the gamma lut for later. However,
>> it saves it to the gamma_store which should already be up to date with what
>> .gamma_get would return and is thus a nop. So, zap it.
>
> Removing drm_fb_helper_save_lut_atomic should be a separate patch I
> think.
Then 3 patches would be needed, first some hybrid thing that does it the
old way, but also stores the lut in .gamma_store, then the split-out that
removes drm_fb_helper_save_lut_atomic, then whatever is needed to get
to the desired code. I can certainly do that, but do you want me to?
I.e., the statement that drm_fb_helper_save_lut_atomic is a nop is only
true when (part of) the other patch is also considered.
>> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
>
>> ---
>> drivers/gpu/drm/drm_fb_helper.c | 131 ++++++++++++----------------------------
>> 1 file changed, 40 insertions(+), 91 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
>> index 574af01..cc2d55d 100644
>> --- a/drivers/gpu/drm/drm_fb_helper.c
>> +++ b/drivers/gpu/drm/drm_fb_helper.c
>> @@ -229,22 +229,6 @@ int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
>> }
>> EXPORT_SYMBOL(drm_fb_helper_remove_one_connector);
>>
>> -static void drm_fb_helper_save_lut_atomic(struct drm_crtc *crtc, struct drm_fb_helper *helper)
>> -{
>> - uint16_t *r_base, *g_base, *b_base;
>> - int i;
>> -
>> - if (helper->funcs->gamma_get == NULL)
>> - return;
>> -
>> - r_base = crtc->gamma_store;
>> - g_base = r_base + crtc->gamma_size;
>> - b_base = g_base + crtc->gamma_size;
>> -
>> - for (i = 0; i < crtc->gamma_size; i++)
>> - helper->funcs->gamma_get(crtc, &r_base[i], &g_base[i], &b_base[i], i);
>> -}
>> -
>> static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
>> {
>> uint16_t *r_base, *g_base, *b_base;
>> @@ -285,7 +269,6 @@ int drm_fb_helper_debug_enter(struct fb_info *info)
>> if (drm_drv_uses_atomic_modeset(mode_set->crtc->dev))
>> continue;
>>
>> - drm_fb_helper_save_lut_atomic(mode_set->crtc, helper);
>> funcs->mode_set_base_atomic(mode_set->crtc,
>> mode_set->fb,
>> mode_set->x,
>> @@ -1167,50 +1150,6 @@ void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
>> }
>> EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);
>>
>> -static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
>> - u16 blue, u16 regno, struct fb_info *info)
>> -{
>> - struct drm_fb_helper *fb_helper = info->par;
>> - struct drm_framebuffer *fb = fb_helper->fb;
>> -
>> - if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
>
> This case here seems gone, and it was also the pièce de résistance when I
> tried tackling fbdev lut support. As far as I understand this stuff we do
> not support FB_VISUAL_TRUECOLOR palette, and all that bitshifting here is
> pointless. But I'm honestly not really clear.
Oops, sorry, I simply missed that, I'll have a closer look...
> I think removing this case should also be a separate patch, and I'd very
> much prefer that someone with some fbdev-clue would ack it.
>
>> - u32 *palette;
>> - u32 value;
>> - /* place color in psuedopalette */
>> - if (regno > 16)
>> - return -EINVAL;
>> - palette = (u32 *)info->pseudo_palette;
>> - red >>= (16 - info->var.red.length);
>> - green >>= (16 - info->var.green.length);
>> - blue >>= (16 - info->var.blue.length);
>> - value = (red << info->var.red.offset) |
>> - (green << info->var.green.offset) |
>> - (blue << info->var.blue.offset);
>> - if (info->var.transp.length > 0) {
>> - u32 mask = (1 << info->var.transp.length) - 1;
>> -
>> - mask <<= info->var.transp.offset;
>> - value |= mask;
>> - }
>> - palette[regno] = value;
>> - return 0;
>> - }
>> -
>> - /*
>> - * The driver really shouldn't advertise pseudo/directcolor
>> - * visuals if it can't deal with the palette.
>> - */
>> - if (WARN_ON(!fb_helper->funcs->gamma_set ||
>> - !fb_helper->funcs->gamma_get))
>> - return -EINVAL;
>> -
>> - WARN_ON(fb->format->cpp[0] != 1);
>> -
>> - fb_helper->funcs->gamma_set(crtc, red, green, blue, regno);
>> -
>> - return 0;
>> -}
>> -
>> /**
>> * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
>> * @cmap: cmap to set
>> @@ -1220,51 +1159,61 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
>> {
>> struct drm_fb_helper *fb_helper = info->par;
>> struct drm_device *dev = fb_helper->dev;
>> - const struct drm_crtc_helper_funcs *crtc_funcs;
>> - u16 *red, *green, *blue, *transp;
>> + struct drm_modeset_acquire_ctx ctx;
>> struct drm_crtc *crtc;
>> - int i, j, rc = 0;
>> - int start;
>> + u16 *r, *g, *b;
>> + int i, ret;
>>
>> if (oops_in_progress)
>> return -EBUSY;
>>
>> - drm_modeset_lock_all(dev);
>> + if (cmap->start + cmap->len < cmap->start)
>> + return -EINVAL;
>> +
>> + drm_modeset_acquire_init(&ctx, 0);
>> +retry:
>> + ret = drm_modeset_lock_all_ctx(dev, &ctx);
>> + if (ret)
>> + goto out;
>> if (!drm_fb_helper_is_bound(fb_helper)) {
>> - drm_modeset_unlock_all(dev);
>> - return -EBUSY;
>> + ret = -EBUSY;
>> + goto out;
>> }
>>
>> for (i = 0; i < fb_helper->crtc_count; i++) {
>> crtc = fb_helper->crtc_info[i].mode_set.crtc;
>> - crtc_funcs = crtc->helper_private;
>> -
>> - red = cmap->red;
>> - green = cmap->green;
>> - blue = cmap->blue;
>> - transp = cmap->transp;
>> - start = cmap->start;
>> + if (!crtc->funcs->gamma_set || !crtc->gamma_size) {
>> + ret = -EINVAL;
>> + goto out;
>> + }
>>
>> - for (j = 0; j < cmap->len; j++) {
>> - u16 hred, hgreen, hblue, htransp = 0xffff;
>> + if (cmap->start + cmap->len > crtc->gamma_size) {
>> + ret = -EINVAL;
>> + goto out;
>> + }
>>
>> - hred = *red++;
>> - hgreen = *green++;
>> - hblue = *blue++;
>> + r = crtc->gamma_store;
>> + g = r + crtc->gamma_size;
>> + b = g + crtc->gamma_size;
>>
>> - if (transp)
>> - htransp = *transp++;
>> + memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(u16));
>> + memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(u16));
>> + memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(u16));
>>
>> - rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
>> - if (rc)
>> - goto out;
>> - }
>> - if (crtc_funcs->load_lut)
>> - crtc_funcs->load_lut(crtc);
>> + ret = crtc->funcs->gamma_set(crtc, r, g, b,
>> + crtc->gamma_size, &ctx);
>> + if (ret)
>> + break;
>> }
>> - out:
>> - drm_modeset_unlock_all(dev);
>> - return rc;
>> +out:
>> + if (ret == -EDEADLK) {
>> + drm_modeset_backoff(&ctx);
>> + goto retry;
>> + }
>> + drm_modeset_drop_locks(&ctx);
>> + drm_modeset_acquire_fini(&ctx);
>> +
>> + return ret;
>
> It's a pre-existing bug, but should we also try to restore the fbdev lut
> in drm_fb_helper_restore_fbdev_mode_unlocked()? Would be yet another bug,
> but might be relevant for your use-case. Just try to run both an fbdev
> application and some kms-native thing, and then SIGKILL the native kms
> app.
>
> But since pre-existing not really required, and probably too much effort.
Good thing too, because I don't really know my way around this code...
Cheers,
peda
> Thanks, Daniel
>
>> }
>> EXPORT_SYMBOL(drm_fb_helper_setcmap);
>>
>> --
>> 2.1.4
>>
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>
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