fc556fb64e
This is a set of fixes for two regressions and one bug in the IOMMU mapping code. It turns out that all of these issues turn up primarily on Tegra30 hardware. The IOMMU mapping bug only manifests on buffers that aren't multiples of the page size. I happened to be testing HDMI with 1080p while writing the code and framebuffers for that happen to fit exactly within 2025 pages of 4 KiB each. One of the regressions is caused by the IOMMU code allocating pages from shmem which can have associated cache lines. If the pages aren't flushed then these cache lines may be flushed later on and cause framebuffer corruption. I'm not sure why I didn't see this before. Perhaps the board that I was using had enough RAM so that the pages shmem would hand out had a better chance of being unused. Or maybe I didn't look too closely. The fix for this is to fake up an SG table so that it can be passed to the DMA API. Ideally this would use drm_clflush_*(), but implementing that for ARM causes DRM to fail to build as a module since some of the low-level cache maintenance functions aren't exported. Hopefully we can get a suitable API exported on ARM for the next release. The second regression is caused by a mismatch between the hardware pipe number and the CRTC's DRM index. These were used inconsistently, which could cause one code location to call drm_vblank_get() with a different pipe than the corresponding drm_vblank_put(), thereby causing the reference count to become unbalanced. Alexandre also reported a possible race condition related to this, which this series also fixes. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABAgAGBQJUkYzSAAoJEN0jrNd/PrOhFWgP+wYiyXiLot7Wo3+HM779fQ9a MZkOycfxyNJ+TxJjvIlJh/2y641G4Elw3rod/QhUKg1b0L2uqVrVRKvEsx5sR5Ci XASwkx9UFLRxN6/Cr/X8SKmE7nFUSwGd3wSoVrT42ldo0DOOlHuVT9NLFoCfDmFa GN5pxUW/WHS7WgCVpG9GgoFmFZXyrwx9ZRHqL49eJqAvjBngmBbZeyhFeZdu71fl rm4qMiLkZZsLZEm3uP53pbdkAf7yZGV3WPWKO43LXgykSMfQ56WcN7JJsGygB3I1 uEMP65Tf3TdynW6Wz2dywq81uITJhd8y6Zhr6j2bsNINTHDz67YOxKfS50axZN/P 2PbqDLyJF7MT1ydQ7weeEv4gkRF8Vt6K3aBfL5gm8PM6jm2sdZytsjLM+/RCIkl3 cDtkC+XmPmGxLTEnV3iWMCbCfOrNvqzkp9jvilIEbxIvgX72T6EQPJnfe7Sv95Cr VBFWoi26XtFhN9wWEGjc7fRTUwNdg4D21/ns8TY3MgOFQcdP01pp2KRTdPDC/6Mt kknXwDaZRY6EjGQmRKkxKf1c64nmY8V7MJx2CSbPc3HgGdSXaa0AOZE2d60beste ASpgMQIbERCmAbdmb5JN6fsKcpJrJL15zbrGcDwSnIk96x4HAC8zB9Xln2ubdCwc IP4cm/Abz6Cfd6I1cQRr =eVlK -----END PGP SIGNATURE----- Merge tag 'drm/tegra/for-3.19-rc1-fixes' of git://people.freedesktop.org/~tagr/linux into drm-fixes drm/tegra: Fixes for v3.19-rc1 This is a set of fixes for two regressions and one bug in the IOMMU mapping code. It turns out that all of these issues turn up primarily on Tegra30 hardware. The IOMMU mapping bug only manifests on buffers that aren't multiples of the page size. I happened to be testing HDMI with 1080p while writing the code and framebuffers for that happen to fit exactly within 2025 pages of 4 KiB each. One of the regressions is caused by the IOMMU code allocating pages from shmem which can have associated cache lines. If the pages aren't flushed then these cache lines may be flushed later on and cause framebuffer corruption. I'm not sure why I didn't see this before. Perhaps the board that I was using had enough RAM so that the pages shmem would hand out had a better chance of being unused. Or maybe I didn't look too closely. The fix for this is to fake up an SG table so that it can be passed to the DMA API. Ideally this would use drm_clflush_*(), but implementing that for ARM causes DRM to fail to build as a module since some of the low-level cache maintenance functions aren't exported. Hopefully we can get a suitable API exported on ARM for the next release. The second regression is caused by a mismatch between the hardware pipe number and the CRTC's DRM index. These were used inconsistently, which could cause one code location to call drm_vblank_get() with a different pipe than the corresponding drm_vblank_put(), thereby causing the reference count to become unbalanced. Alexandre also reported a possible race condition related to this, which this series also fixes. * tag 'drm/tegra/for-3.19-rc1-fixes' of git://people.freedesktop.org/~tagr/linux: drm/tegra: dc: Select root window for event dispatch drm/tegra: gem: Use the proper size for GEM objects drm/tegra: gem: Flush buffer objects upon allocation drm/tegra: dc: Fix a potential race on page-flip completion drm/tegra: dc: Consistently use the same pipe drm/irq: Add drm_crtc_vblank_count() drm/irq: Add drm_crtc_handle_vblank() drm/irq: Add drm_crtc_send_vblank_event() |
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| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| video | ||
| xen | ||
| Kbuild | ||